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[[File:Gecko on My Window 2 (17729540).jpg|thumb|250px|[[Gecko]]s can stick to walls and ceilings because of Van der Waals forces; see the [[#Use by geckos|section below]].]] | |||
In [[physical chemistry]], the '''van der Waals' force''' (or '''van der Waals' interaction'''), named after [[Netherlands|Dutch]] [[scientist]] [[Johannes Diderik van der Waals]], is the sum of the attractive or repulsive forces between [[molecule]]s (or between parts of the same molecule) other than those due to [[covalent bond]]s, the [[hydrogen bonds]], or the [[electrostatic interaction]] of [[ion]]s with one another or with neutral molecules or charged molecules.<ref>{{GoldBookRef | file=V06597 |title=van der Waals forces | year=1994}}</ref> The term includes: | |||
* force between two permanent [[Molecular dipole moment|dipoles]] ([[Keesom force]]) | |||
* force between a permanent [[Molecular dipole moment|dipole]] and a corresponding induced dipole ([[Debye force]]) | |||
* force between two instantaneously induced [[Molecular dipole moment|dipoles]] ([[London dispersion force]]). | |||
It is also sometimes used loosely as a [[synonym]] for the totality of intermolecular forces. Van der Waals' forces are relatively weak compared to covalent bonds, but play a fundamental role in fields as diverse as [[supramolecular chemistry]], [[structural biology]], [[polymer science]], [[nanotechnology]], [[surface science]], and [[condensed matter physics]]. Van der Waals forces define many properties of [[Organic chemistry|organic compounds]], including their solubility in [[Chemical polarity|polar and non-polar]] media. | |||
In low molecular weight [[alcohol]]s, the hydrogen-bonding properties of the polar [[hydroxyl group]] dominate the weaker van der Waals' interactions. | |||
In higher molecular weight alcohols, the properties of the nonpolar hydrocarbon chain(s) dominate and define the solubility. Van der Waals forces quickly vanish at longer distances between interacting molecules. | |||
In 2012, the first direct measurements of the strength of the van der Waals' force for a single organic molecule bound to a metal surface was made via [[Atomic force microscope|atomic force microscopy]] and corroborated with [[Density functional theory|density functional calculations]].<ref>http://www.columbia.edu/~sva2107/media/Aradhya_NMat_2012.pdf</ref> | |||
==Definition== | |||
[[File:Dipole-dipole-interaction-in-HCl-2D.png|200px|right|thumb|Attractive interactions resulting from dipole-dipole interaction of two [[hydrogen chloride]] molecules]] | |||
Van der Waals forces include attractions and repulsions between atoms, molecules, and surfaces, as well as other intermolecular forces. They differ from [[covalent bond|covalent]] and [[ionic bond|ionic]] bonding in that they are caused by correlations in the fluctuating polarizations of nearby particles (a consequence of [[quantum dynamics]]<ref name=Abrikosov> | |||
{{Cite book|author=A.A. Abrikosov, L.P. Gorkov, I.E. Dzyaloshinsky |title=Methods of Quantum Field Theory in Statistical Physics | |||
|year= 1963–1975 |publisher=Dover Publications |isbn=0-486-63228-8 }} | |||
Chapter 6 Electromagnetic Radiation in an Absorbing Medium</ref>). | |||
[[Intermolecular forces]] have four major contributions: | |||
# A repulsive component resulting from the [[Pauli exclusion principle]] that prevents the collapse of molecules. | |||
# Attractive or repulsive [[electrostatic]] interactions between permanent charges (in the case of molecular ions), dipoles (in the case of molecules without inversion center), [[quadrupole]]s (all molecules with symmetry lower than cubic), and in general between permanent [[multipole]]s. The electrostatic interaction is sometimes called the [[Keesom force|Keesom interaction]] or Keesom force after [[Willem Hendrik Keesom]]. | |||
# Induction (also known as [[polarizability|polarization]]), which is the attractive interaction between a permanent multipole on one molecule with an induced multipole on another. This interaction is sometimes called Debye force after [[Peter J.W. Debye]]. | |||
# Dispersion (usually named after [[Fritz London]]), which is the attractive interaction between any pair of molecules, including non-polar atoms, arising from the interactions of instantaneous multipoles. | |||
Returning to nomenclature, different texts refer to different things using the term "van der Waals force". Some texts mean by the van der Waals' force the totality of forces (including repulsion); others mean all the attractive forces (and then sometimes distinguish van der Waals-Keesom, van der Waals-Debye, and van der Waals-London). | |||
All intermolecular/van der Waals' forces are [[anisotropic]] (except those between two noble gas atoms), which means that they depend on the relative orientation of the molecules. The induction and dispersion interactions are always attractive, irrespective of orientation, but the electrostatic interaction changes sign upon rotation of the molecules. That is, the electrostatic force can be attractive or repulsive, depending on the mutual orientation of the molecules. When molecules are in thermal motion, as they are in the gas and liquid phase, the electrostatic force is averaged out to a large extent, because the molecules thermally rotate and thus probe both repulsive and attractive parts of the electrostatic force. Sometimes this effect is expressed by the statement that "random thermal motion around room temperature can usually overcome or disrupt them" (which refers to the electrostatic component of the van der Waals force). Clearly, the thermal averaging effect is much less pronounced for the attractive induction and dispersion forces. | |||
The [[Lennard-Jones potential]] is often used as an approximate model for the isotropic part of a total (repulsion plus attraction) van der Waals' force as a function of distance. | |||
Van der Waals forces are responsible for certain cases of pressure broadening ([[van der Waals broadening]]) of spectral lines and the formation of [[van der Waals molecules]].<!-- most use "van der Waals molecules" ([http://pubs.acs.org/doi/abs/10.1021/cr00088a008], [http://www.wesleyan.edu/chem/faculty/novick/vdw.html], [http://doi.wiley.com/10.1002/anie.197204861], [http://books.google.it/books?id=PP6vtMJlWowC&pg=PA220&lpg=PA220&dq=%22Van+der+Waals+molecules%22+-wikipedia&source=bl&ots=BVJSlFvb3a&sig=_vVlFYe7_vEWrNL07sVm9NF8dDs&hl=en&ei=6ogSS8eICJOZjAeJkLXLAw&sa=X&oi=book_result&ct=result&resnum=4&ved=0CBIQ6AEwAw]) few use "Van" ([http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TFN-4CNJCXP-2&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1113973534&_rerunOrigin=google&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=31e5934c994d877beafb7c335e513529], [http://www.infography.com/content/718688290900.html] (just a search aggregator)) --> The London-van der Waals forces<!-- see [http://www.clarkson.edu/projects/crcd/me437/downloads/5_vanderWaals.pdf] and [http://linkinghub.elsevier.com/retrieve/pii/S1672251507601560] --> are related to the [[Casimir effect]] for dielectric media, the former being the microscopic description of the latter bulk property. The first detailed calculations of this were done in 1955 by [[Evgeny Mikhailovich Lifshitz|E. M. Lifshitz]].<ref>For further investigation, one may consult the University of St. Andrews' levitation work in a popular article: [http://www.sciencedaily.com/releases/2007/08/070806091137.htm Science Journal: ''New way to levitate objects discovered''], and in a more scholarly version: [http://www.iop.org/EJ/article/1367-2630/9/8/254/njp7_8_254.html New Journal of Physics: ''Quantum levitation by left-handed metamaterials''], which relate the Casimir effect to the gecko and how the reversal of the Casimir effect can result in physical levitation of tiny objects.</ref> | |||
A general theory of Lifshitz van der Waals' forces was developed in 1961 by I. E. Dzyaloshinskii, et al. <ref>{{cite journal|last1= Dzyaloshinskii|first1= I E|last2= Lifshitz|first2= E M|last3= Pitaevskii|first3= Lev P|title= GENERAL THEORY OF VAN DER WAALS' FORCES|journal= Soviet Physics Uspekhi|volume= 4|pages= 153|year= 1961|doi= 10.1070/PU1961v004n02ABEH003330|bibcode=1961SvPhU...4..153D|issue= 2}}</ref> In 2011, Y. Zheng and A. Narayanaswamy <ref>{{cite journal|last1= Zheng|first1= Y.|last2= Narayanaswamy|first2= A.|title= Lifshitz Theory of van der Waals Pressure in Dissipative Media|journal= Phys. Rev. A|volume= 83|pages= 042504 |year= 2011|doi=10.1103/PhysRevA.83.042504|arxiv = 1011.5433 |bibcode = 2011PhRvA..83d2504Z }}</ref> provided a alternate formalism for calculating van der Waals or Casimir pressure. | |||
==London dispersion force== | |||
{{Main|London dispersion force}} | |||
London dispersion forces, named after the German-American physicist [[Fritz London]], are weak [[intermolecular force]]s that arise from the interactive forces between instantaneous multipoles in [[molecule]]s without permanent [[multipole moments]]. These forces dominate the interaction of non-polar molecules, and also play a less significant role in van der Waals forces than molecules containing permanent dipoles or ionized molecules. London dispersion forces are also known as [[London dispersion force|dispersion]] forces, London forces, or instantaneous dipole–induced dipole forces. They increase with the molar mass, causing a higher boiling point especially for the halogen group. | |||
==Van der Waals' forces between macroscopic objects== | |||
For macroscopic bodies with known volumes and numbers of atoms or molecules per unit volume, the total van der Waals force is often computed based on the "microscopic theory" as the sum over all interacting pairs. It is necessary to integrate over the total volume of the object, which makes the calculation dependent on the objects' shapes. For example, the van der Waals' interaction energy between spherical bodies of radii R<sub>1</sub> and R<sub>2</sub> and with smooth surfaces was approximated in 1937 by [[H. C. Hamaker|Hamaker]]<ref>H. C. Hamaker, Physica, 4(10), 1058-1072 (1937)</ref> (using London's famous 1937 equation for the [[London dispersion force|dispersion interaction energy]] between atoms/molecules<ref>F. London, Transactions of the Faraday Society, 33, 8-26 (1937)</ref> as the starting point) by: | |||
{{NumBlk|:| | |||
<math>\begin{align} | |||
&U(z;R_{1},R_{2})\\ | |||
= -&\frac{A}{6}\left(\frac{2R_{1}R_{2}}{z^2 - (R_{1} + R_{2})^2} + \frac{2R_{1}R_{2}}{z^2 - (R_{1} - R_{2})^2} + \ln\left[\frac{z^2-(R_{1}+ R_{2})^2}{z^2-(R_{1}- R_{2})^2}\right]\right) | |||
\end{align}</math>|{{EquationRef|1}}}} | |||
where A is the [[Hamaker constant|Hamaker coefficient]], which is a constant (~10<sup>−19</sup> − 10<sup>−20</sup> J) that depends on the material properties (it can be positive or negative in sign depending on the intervening medium), and ''z'' is the center-to-center distance; i.e., the sum of ''R''<sub>1</sub>, ''R''<sub>2</sub>, and ''r'' (the distance between the surfaces): <math>\ z = R_{1} + R_{2} + r</math>. | |||
In the limit of close-approach, the spheres are sufficiently large compared to the distance between them; i.e., <math>\ r \ll R_{1} or R_{2}</math>, so that equation (1) for the potential energy function simplifies to: | |||
{{NumBlk|:|<math>\ U(r;R_{1},R_{2})= -\frac{AR_{1}R_{2}}{(R_{1}+R_{2})6r}</math>|{{EquationRef|2}}}} | |||
The van der Waals' ''[[force]]'' between two spheres of constant radii (''R''<sub>1</sub> and ''R''<sub>2</sub> are treated as parameters) is then a function of separation since the force on an object is the negative of the derivative of the potential energy function,<math>\ F_{VW}(r) = -\frac{d}{dr}U(r)</math>. This yields: | |||
{{NumBlk|:|<math>\ F_{VW}(r)= -\frac{AR_{1}R_{2}}{(R_{1}+R_{2})6r^2}</math>|{{EquationRef|3}}}} | |||
The van der Waals forces between objects with other geometries using the Hamaker model have been published in the literature.<ref>R. Tadmor, JOURNAL OF PHYSICS: CONDENSED MATTER, 13 (2001) L195–L202</ref><ref>Israelachvili J., ''Intermolecular and Surface Forces'', Academic Press (1985–2004), ISBN 0-12-375181-0</ref><ref>V. A. Parsegian, "Van der Waals Forces: A Handbook for Biologists, Chemists, Engineers, and Physicists," Cambridge University Press (2006) ISBN 978-0-521-83906-8</ref> | |||
From the expression above, it is seen that the van der Waals force decreases with decreasing particle size (R). Nevertheless, the strength of inertial forces, such as gravity and drag/lift, decrease to a greater extent. Consequently, the van der Waals forces become dominant for collections of very small particles such as very fine-grained dry powders (where there are no capillary forces present) even though the force of attraction is smaller in magnitude than it is for larger particles of the same substance. Such powders are said to be cohesive, meaning they are not as easily fluidized or pneumatically conveyed as easily as their more coarse-grained counterparts. Generally, free-flow occurs with particles greater than about 250 μm. | |||
The van der Waals' force of adhesion is also dependent on the surface topography. If there are surface asperities, or protuberances, that result in a greater total area of contact between two particles or between a particle and a wall, this increases the van der Waals force of attraction as well as the tendency for mechanical interlocking. | |||
The microscopic theory assumes pairwise additivity. It neglects [[Many-body problem|many-body interactions]] and [[Retarded potential|retardation]]. A more rigorous approach accounting for these effects, called the "macroscopic theory," was developed by [[Evgeny Lifshitz|Lifshitz]] in 1956.<ref>E. M. Lifshitz, Soviet Phys. JETP, 2, 73 (1956)</ref> [[D. Langbein|Langbein]] derived a much more cumbersome "exact" expression in 1970 for spherical bodies within the framework of the Lifshitz theory<ref>D. Langbein, Phys. Rev. B, 2, 3371 (1970)</ref> while a simpler macroscopic model approximation had been made by [[Boris Derjaguin|Derjaguin]] as early as 1934.<ref>B. V. Derjaguin, Kolloid-Z., 69, 155-64 (1934)</ref> Expressions for the van der Waals forces for many different geometries using the Lifshitz theory have likewise been published. | |||
==Use by geckos== | |||
[[Image:Gecko Leaftail 1.jpg|thumb|right|300px|[[Gecko]] climbing glass]] | |||
The ability of [[gecko]]s – which can hang on a glass surface using only one toe – to climb on sheer surfaces has been attributed to the van der Waals forces between these surfaces and the spatulae (plural of spatula), or microscopic projections, which cover the hair-like setae found on their footpads.<ref>[http://media-relations.www.clemson.edu/article.php?article_id=2122 Researchers discover how geckos know when to hold tight]. Clemson.edu. Retrieved on 2011-01-08.</ref><ref>{{cite journal|author=Autumn, K. ''et al.''|title=Evidence for van der Waals adhesion in gecko setae|journal=Proceedings of the National Academy of Sciences|volume=99|pages=12252–6|year=2002|doi=10.1073/pnas.192252799|pmid=12198184|issue=19|pmc=129431|bibcode = 2002PNAS...9912252A }}</ref> A later study suggested that capillary adhesion might play a role,<ref>{{cite journal|author=Huber, G., ''et al.''|title=Evidence for capillarity contributions to gecko adhesion from single spatula nanomechanical measurements|journal=Proceedings of the National Academy of Sciences|volume=102|pages=16293–6|year=2005|doi=10.1073/pnas.0506328102|pmid=16260737|issue=45|pmc=1283435|bibcode = 2005PNAS..10216293H }}</ref> but that hypothesis has been rejected by more recent studies.<ref>{{cite journal|author=Chen, B.|coauthors=Gao, H.|title= An alternative explanation of the effect of humidity in gecko adhesion: stiffness reduction enhances adhesion on a rough surface|journal= Int JAppl Mech|volume=2|pages=1–9|year=2010|doi=10.1142/s1758825110000433|bibcode = 2010IJAM...02....1C }}</ref><ref>{{cite journal|author=Puthoff, J. B., ''et al.''|title= Changes in materials properties explain the effects of humidity on gecko adhesion|journal=J Exp Biol|volume=213|pages= 3699–3704|doi=10.1242/jeb.047654|year=2010|issue=21}}</ref><ref>{{cite journal|author=Prowse, M. S., ''et al.''|title= Effects of humidity on the mechanical properties of gecko setae|journal=Acta Biomater|volume=7|pages=733–738|doi= 10.1016/j.actbio.2010.09.036|year=2011|issue=2|pmid=20920615}}</ref> There were efforts in 2008 to create a [[dry glue]] that exploits the effect,<ref>[http://www.reuters.com/article/scienceNews/idUSN0942431020081009?sp=true Gecko-like glue is said to be stickiest yet], "reuters.com" 8 October 2008</ref> and success was achieved in 2011 to create an adhesive tape on similar grounds.<ref>[http://www.gizmag.com/bioinspired-adhesive-tape-kiel/20406/ Biologically inspired adhesive tape can be reused thousands of times Biologically inspired adhesive tape can be reused thousands of times]</ref> In 2011, a paper was published relating the effect to both velcro-like hairs and the presence of lipids in gecko footprints.<ref>[http://www.physorg.com/news/2011-08-scientists-gecko-footprint-clue.html Scientists trace gecko footprint, find clue to glue]</ref> | |||
==See also== | |||
* [[Stochastic electrodynamics]] | |||
==References== | |||
{{Reflist|2}} | |||
==Further reading== | |||
* Iver Brevik, V. N. Marachevsky, Kimball A. Milton, ''Identity of the Van der Waals Force and the Casimir Effect and the Irrelevance of these Phenomena to Sonoluminescence'', [http://arxiv.org/abs/hep-th/9901011 hep-th/9901011] | |||
* I. D. Dzyaloshinskii, E. M. Lifshitz, and L. P. Pitaevskii, ''Usp. Fiz. Nauk'' '''73''', 381 (1961) | |||
**English translation: ''Soviet Phys. Usp.'' '''4''', 153 (1961) | |||
*L. D. Landau and E. M. Lifshitz, Electrodynamics of Continuous Media, Pergamon, Oxford, 1960, pp. 368–376. | |||
*[[Dieter Langbein]], "''[Langbein, Dieter Theory of Van der Waals Attraction, ( Springer-Verlag New York Heidelberg 1974)]''" | |||
* Mark Lefers, "''[http://www.biochem.northwestern.edu/holmgren/Glossary/Definitions/Def-V/Van_der_Waals_force.html Van der Waals dispersion force]''". Holmgren Lab. | |||
*E. M. Lifshitz, ''Zh. Eksp. Teor. Fiz.'' '''29''', 894 (1955) | |||
**English translation: ''Soviet Phys. JETP'' '''2''', 73 (1956) | |||
* Western Oregon University's "''[http://www.wou.edu/las/physci/ch334/lecture/intermol/london.htm London force]''". [http://www.wou.edu/las/physci/ch334/lecture/intermol/ Intermolecular Forces]. (animation) | |||
* J. Lyklema, Fundamentals of Interface and Colloid Science, page 4.43 | |||
* Israelachvili J., ''Intermolecular and Surface Forces'', Academic Press (1985–2004), ISBN 0-12-375181-0 | |||
==External links== | |||
* {{cite web | |||
| url = http://antoine.frostburg.edu/chem/senese/101/liquids/faq/h-bonding-vs-london-forces.shtml | |||
| title = What are van der Waals forces? | |||
| first = Fred | last = Senese | |||
| publisher = Frostburg State University | |||
| year = 1999 | accessdate = March 2010 | |||
}} An introductory description of the van der Waals force (as a sum of attractive components only) | |||
*[http://www.ted.com/talks/lang/eng/robert_full_learning_from_the_gecko_s_tail.html Robert Full: Learning from the gecko's tail.] TED Talk on biomimicry, including applications of Van der Waals force. | |||
{{Chemical bonds}} | |||
{{DEFAULTSORT:Van Der Waals Force}} | |||
[[Category:Intermolecular forces]] | |||
Revision as of 20:57, 31 January 2014
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In physical chemistry, the van der Waals' force (or van der Waals' interaction), named after Dutch scientist Johannes Diderik van der Waals, is the sum of the attractive or repulsive forces between molecules (or between parts of the same molecule) other than those due to covalent bonds, the hydrogen bonds, or the electrostatic interaction of ions with one another or with neutral molecules or charged molecules.[1] The term includes:
- force between two permanent dipoles (Keesom force)
- force between a permanent dipole and a corresponding induced dipole (Debye force)
- force between two instantaneously induced dipoles (London dispersion force).
It is also sometimes used loosely as a synonym for the totality of intermolecular forces. Van der Waals' forces are relatively weak compared to covalent bonds, but play a fundamental role in fields as diverse as supramolecular chemistry, structural biology, polymer science, nanotechnology, surface science, and condensed matter physics. Van der Waals forces define many properties of organic compounds, including their solubility in polar and non-polar media.
In low molecular weight alcohols, the hydrogen-bonding properties of the polar hydroxyl group dominate the weaker van der Waals' interactions. In higher molecular weight alcohols, the properties of the nonpolar hydrocarbon chain(s) dominate and define the solubility. Van der Waals forces quickly vanish at longer distances between interacting molecules.
In 2012, the first direct measurements of the strength of the van der Waals' force for a single organic molecule bound to a metal surface was made via atomic force microscopy and corroborated with density functional calculations.[2]
Definition
Van der Waals forces include attractions and repulsions between atoms, molecules, and surfaces, as well as other intermolecular forces. They differ from covalent and ionic bonding in that they are caused by correlations in the fluctuating polarizations of nearby particles (a consequence of quantum dynamics[3]).
Intermolecular forces have four major contributions:
- A repulsive component resulting from the Pauli exclusion principle that prevents the collapse of molecules.
- Attractive or repulsive electrostatic interactions between permanent charges (in the case of molecular ions), dipoles (in the case of molecules without inversion center), quadrupoles (all molecules with symmetry lower than cubic), and in general between permanent multipoles. The electrostatic interaction is sometimes called the Keesom interaction or Keesom force after Willem Hendrik Keesom.
- Induction (also known as polarization), which is the attractive interaction between a permanent multipole on one molecule with an induced multipole on another. This interaction is sometimes called Debye force after Peter J.W. Debye.
- Dispersion (usually named after Fritz London), which is the attractive interaction between any pair of molecules, including non-polar atoms, arising from the interactions of instantaneous multipoles.
Returning to nomenclature, different texts refer to different things using the term "van der Waals force". Some texts mean by the van der Waals' force the totality of forces (including repulsion); others mean all the attractive forces (and then sometimes distinguish van der Waals-Keesom, van der Waals-Debye, and van der Waals-London).
All intermolecular/van der Waals' forces are anisotropic (except those between two noble gas atoms), which means that they depend on the relative orientation of the molecules. The induction and dispersion interactions are always attractive, irrespective of orientation, but the electrostatic interaction changes sign upon rotation of the molecules. That is, the electrostatic force can be attractive or repulsive, depending on the mutual orientation of the molecules. When molecules are in thermal motion, as they are in the gas and liquid phase, the electrostatic force is averaged out to a large extent, because the molecules thermally rotate and thus probe both repulsive and attractive parts of the electrostatic force. Sometimes this effect is expressed by the statement that "random thermal motion around room temperature can usually overcome or disrupt them" (which refers to the electrostatic component of the van der Waals force). Clearly, the thermal averaging effect is much less pronounced for the attractive induction and dispersion forces.
The Lennard-Jones potential is often used as an approximate model for the isotropic part of a total (repulsion plus attraction) van der Waals' force as a function of distance.
Van der Waals forces are responsible for certain cases of pressure broadening (van der Waals broadening) of spectral lines and the formation of van der Waals molecules. The London-van der Waals forces are related to the Casimir effect for dielectric media, the former being the microscopic description of the latter bulk property. The first detailed calculations of this were done in 1955 by E. M. Lifshitz.[4]
A general theory of Lifshitz van der Waals' forces was developed in 1961 by I. E. Dzyaloshinskii, et al. [5] In 2011, Y. Zheng and A. Narayanaswamy [6] provided a alternate formalism for calculating van der Waals or Casimir pressure.
London dispersion force
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London dispersion forces, named after the German-American physicist Fritz London, are weak intermolecular forces that arise from the interactive forces between instantaneous multipoles in molecules without permanent multipole moments. These forces dominate the interaction of non-polar molecules, and also play a less significant role in van der Waals forces than molecules containing permanent dipoles or ionized molecules. London dispersion forces are also known as dispersion forces, London forces, or instantaneous dipole–induced dipole forces. They increase with the molar mass, causing a higher boiling point especially for the halogen group.
Van der Waals' forces between macroscopic objects
For macroscopic bodies with known volumes and numbers of atoms or molecules per unit volume, the total van der Waals force is often computed based on the "microscopic theory" as the sum over all interacting pairs. It is necessary to integrate over the total volume of the object, which makes the calculation dependent on the objects' shapes. For example, the van der Waals' interaction energy between spherical bodies of radii R1 and R2 and with smooth surfaces was approximated in 1937 by Hamaker[7] (using London's famous 1937 equation for the dispersion interaction energy between atoms/molecules[8] as the starting point) by:
where A is the Hamaker coefficient, which is a constant (~10−19 − 10−20 J) that depends on the material properties (it can be positive or negative in sign depending on the intervening medium), and z is the center-to-center distance; i.e., the sum of R1, R2, and r (the distance between the surfaces): .
In the limit of close-approach, the spheres are sufficiently large compared to the distance between them; i.e., , so that equation (1) for the potential energy function simplifies to:
The van der Waals' force between two spheres of constant radii (R1 and R2 are treated as parameters) is then a function of separation since the force on an object is the negative of the derivative of the potential energy function,. This yields:
The van der Waals forces between objects with other geometries using the Hamaker model have been published in the literature.[9][10][11]
From the expression above, it is seen that the van der Waals force decreases with decreasing particle size (R). Nevertheless, the strength of inertial forces, such as gravity and drag/lift, decrease to a greater extent. Consequently, the van der Waals forces become dominant for collections of very small particles such as very fine-grained dry powders (where there are no capillary forces present) even though the force of attraction is smaller in magnitude than it is for larger particles of the same substance. Such powders are said to be cohesive, meaning they are not as easily fluidized or pneumatically conveyed as easily as their more coarse-grained counterparts. Generally, free-flow occurs with particles greater than about 250 μm.
The van der Waals' force of adhesion is also dependent on the surface topography. If there are surface asperities, or protuberances, that result in a greater total area of contact between two particles or between a particle and a wall, this increases the van der Waals force of attraction as well as the tendency for mechanical interlocking.
The microscopic theory assumes pairwise additivity. It neglects many-body interactions and retardation. A more rigorous approach accounting for these effects, called the "macroscopic theory," was developed by Lifshitz in 1956.[12] Langbein derived a much more cumbersome "exact" expression in 1970 for spherical bodies within the framework of the Lifshitz theory[13] while a simpler macroscopic model approximation had been made by Derjaguin as early as 1934.[14] Expressions for the van der Waals forces for many different geometries using the Lifshitz theory have likewise been published.
Use by geckos
The ability of geckos – which can hang on a glass surface using only one toe – to climb on sheer surfaces has been attributed to the van der Waals forces between these surfaces and the spatulae (plural of spatula), or microscopic projections, which cover the hair-like setae found on their footpads.[15][16] A later study suggested that capillary adhesion might play a role,[17] but that hypothesis has been rejected by more recent studies.[18][19][20] There were efforts in 2008 to create a dry glue that exploits the effect,[21] and success was achieved in 2011 to create an adhesive tape on similar grounds.[22] In 2011, a paper was published relating the effect to both velcro-like hairs and the presence of lipids in gecko footprints.[23]
See also
References
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Further reading
- Iver Brevik, V. N. Marachevsky, Kimball A. Milton, Identity of the Van der Waals Force and the Casimir Effect and the Irrelevance of these Phenomena to Sonoluminescence, hep-th/9901011
- I. D. Dzyaloshinskii, E. M. Lifshitz, and L. P. Pitaevskii, Usp. Fiz. Nauk 73, 381 (1961)
- English translation: Soviet Phys. Usp. 4, 153 (1961)
- L. D. Landau and E. M. Lifshitz, Electrodynamics of Continuous Media, Pergamon, Oxford, 1960, pp. 368–376.
- Dieter Langbein, "[Langbein, Dieter Theory of Van der Waals Attraction, ( Springer-Verlag New York Heidelberg 1974)]"
- Mark Lefers, "Van der Waals dispersion force". Holmgren Lab.
- E. M. Lifshitz, Zh. Eksp. Teor. Fiz. 29, 894 (1955)
- English translation: Soviet Phys. JETP 2, 73 (1956)
- Western Oregon University's "London force". Intermolecular Forces. (animation)
- J. Lyklema, Fundamentals of Interface and Colloid Science, page 4.43
- Israelachvili J., Intermolecular and Surface Forces, Academic Press (1985–2004), ISBN 0-12-375181-0
External links
- Template:Cite web An introductory description of the van der Waals force (as a sum of attractive components only)
- Robert Full: Learning from the gecko's tail. TED Talk on biomimicry, including applications of Van der Waals force.
- ↑ Template:GoldBookRef
- ↑ http://www.columbia.edu/~sva2107/media/Aradhya_NMat_2012.pdf
- ↑
20 year-old Real Estate Agent Rusty from Saint-Paul, has hobbies and interests which includes monopoly, property developers in singapore and poker. Will soon undertake a contiki trip that may include going to the Lower Valley of the Omo.
My blog: http://www.primaboinca.com/view_profile.php?userid=5889534 Chapter 6 Electromagnetic Radiation in an Absorbing Medium - ↑ For further investigation, one may consult the University of St. Andrews' levitation work in a popular article: Science Journal: New way to levitate objects discovered, and in a more scholarly version: New Journal of Physics: Quantum levitation by left-handed metamaterials, which relate the Casimir effect to the gecko and how the reversal of the Casimir effect can result in physical levitation of tiny objects.
- ↑ One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting
In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang
Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules
Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.
A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running
The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more
There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang - ↑ One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting
In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang
Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules
Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.
A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running
The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more
There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang - ↑ H. C. Hamaker, Physica, 4(10), 1058-1072 (1937)
- ↑ F. London, Transactions of the Faraday Society, 33, 8-26 (1937)
- ↑ R. Tadmor, JOURNAL OF PHYSICS: CONDENSED MATTER, 13 (2001) L195–L202
- ↑ Israelachvili J., Intermolecular and Surface Forces, Academic Press (1985–2004), ISBN 0-12-375181-0
- ↑ V. A. Parsegian, "Van der Waals Forces: A Handbook for Biologists, Chemists, Engineers, and Physicists," Cambridge University Press (2006) ISBN 978-0-521-83906-8
- ↑ E. M. Lifshitz, Soviet Phys. JETP, 2, 73 (1956)
- ↑ D. Langbein, Phys. Rev. B, 2, 3371 (1970)
- ↑ B. V. Derjaguin, Kolloid-Z., 69, 155-64 (1934)
- ↑ Researchers discover how geckos know when to hold tight. Clemson.edu. Retrieved on 2011-01-08.
- ↑ One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting
In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang
Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules
Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.
A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running
The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more
There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang - ↑ One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting
In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang
Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules
Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.
A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running
The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more
There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang - ↑ One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting
In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang
Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules
Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.
A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running
The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more
There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang - ↑ One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting
In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang
Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules
Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.
A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running
The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more
There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang - ↑ One of the biggest reasons investing in a Singapore new launch is an effective things is as a result of it is doable to be lent massive quantities of money at very low interest rates that you should utilize to purchase it. Then, if property values continue to go up, then you'll get a really high return on funding (ROI). Simply make sure you purchase one of the higher properties, reminiscent of the ones at Fernvale the Riverbank or any Singapore landed property Get Earnings by means of Renting
In its statement, the singapore property listing - website link, government claimed that the majority citizens buying their first residence won't be hurt by the new measures. Some concessions can even be prolonged to chose teams of consumers, similar to married couples with a minimum of one Singaporean partner who are purchasing their second property so long as they intend to promote their first residential property. Lower the LTV limit on housing loans granted by monetary establishments regulated by MAS from 70% to 60% for property purchasers who are individuals with a number of outstanding housing loans on the time of the brand new housing purchase. Singapore Property Measures - 30 August 2010 The most popular seek for the number of bedrooms in Singapore is 4, followed by 2 and three. Lush Acres EC @ Sengkang
Discover out more about real estate funding in the area, together with info on international funding incentives and property possession. Many Singaporeans have been investing in property across the causeway in recent years, attracted by comparatively low prices. However, those who need to exit their investments quickly are likely to face significant challenges when trying to sell their property – and could finally be stuck with a property they can't sell. Career improvement programmes, in-house valuation, auctions and administrative help, venture advertising and marketing, skilled talks and traisning are continuously planned for the sales associates to help them obtain better outcomes for his or her shoppers while at Knight Frank Singapore. No change Present Rules
Extending the tax exemption would help. The exemption, which may be as a lot as $2 million per family, covers individuals who negotiate a principal reduction on their existing mortgage, sell their house short (i.e., for lower than the excellent loans), or take part in a foreclosure course of. An extension of theexemption would seem like a common-sense means to assist stabilize the housing market, but the political turmoil around the fiscal-cliff negotiations means widespread sense could not win out. Home Minority Chief Nancy Pelosi (D-Calif.) believes that the mortgage relief provision will be on the table during the grand-cut price talks, in response to communications director Nadeam Elshami. Buying or promoting of blue mild bulbs is unlawful.
A vendor's stamp duty has been launched on industrial property for the primary time, at rates ranging from 5 per cent to 15 per cent. The Authorities might be trying to reassure the market that they aren't in opposition to foreigners and PRs investing in Singapore's property market. They imposed these measures because of extenuating components available in the market." The sale of new dual-key EC models will even be restricted to multi-generational households only. The models have two separate entrances, permitting grandparents, for example, to dwell separately. The vendor's stamp obligation takes effect right this moment and applies to industrial property and plots which might be offered inside three years of the date of buy. JLL named Best Performing Property Brand for second year running
The data offered is for normal info purposes only and isn't supposed to be personalised investment or monetary advice. Motley Fool Singapore contributor Stanley Lim would not personal shares in any corporations talked about. Singapore private home costs increased by 1.eight% within the fourth quarter of 2012, up from 0.6% within the earlier quarter. Resale prices of government-built HDB residences which are usually bought by Singaporeans, elevated by 2.5%, quarter on quarter, the quickest acquire in five quarters. And industrial property, prices are actually double the levels of three years ago. No withholding tax in the event you sell your property. All your local information regarding vital HDB policies, condominium launches, land growth, commercial property and more
There are various methods to go about discovering the precise property. Some local newspapers (together with the Straits Instances ) have categorised property sections and many local property brokers have websites. Now there are some specifics to consider when buying a 'new launch' rental. Intended use of the unit Every sale begins with 10 p.c low cost for finish of season sale; changes to 20 % discount storewide; follows by additional reduction of fiftyand ends with last discount of 70 % or extra. Typically there is even a warehouse sale or transferring out sale with huge mark-down of costs for stock clearance. Deborah Regulation from Expat Realtor shares her property market update, plus prime rental residences and houses at the moment available to lease Esparina EC @ Sengkang - ↑ Gecko-like glue is said to be stickiest yet, "reuters.com" 8 October 2008
- ↑ Biologically inspired adhesive tape can be reused thousands of times Biologically inspired adhesive tape can be reused thousands of times
- ↑ Scientists trace gecko footprint, find clue to glue