Van der Waais

MoKeiiar A R W 1982 infrared speotra of hydrogen-rare gas Van der Waais moieouies Faraday Discuss. Chem. Soc. 73 89-108... 

Love]oy C M, Sohuder M D and Nesbitt D J 1986 High resoiution iR iaser speotrosoopy of Van der Waais oompiexes in siit supersonio ]ets observation and anaiysis of and + 2V3 in ArHF J. Chem. Phys. 85 4890-902... 

Also Equation of state for ideai gases (from the continuum theory) van der Waais Equation a ... 

Forces found between haiogen moiecuies are van der Waais forces, which are due to temporariiy induced dipoies caused by poiarization of eiectron ciouds. ... 

Therefore, greater poiarization of eiectron cioud wouid cause greater attractive force (van der Waais force), resuiting in higher boiiing points. ... 

Historical deveiopment of van der Waais forces. The Lennard-Jones potentiai. intermoiecuiar forces. Van der Waais forces between surfaces and coiioids. The Hamaker constant. The DLVO theory of coi-loidal stability. 

Historical development of van der Waais forces and the Lennard-Jones potential... 

In 1873 van der Waais pointed out that real gases do not obey the ideal gas equation PV = RT and suggested that two correction terms should be included to give a more accurate representation, of the form (P + ali/) V - b) = RT. The term a/v corrects for the fact that there will be an attractive force between all gas molecules (both polar and nonpolar) and hence the observed pressure must be increased to that of an ideal, non-interacting gas. The second term (b) corrects for the fact that the molecules are finite in size and act like hard spheres on collision the actual free volume must then be less than the total measured volume of the gas. These correction terms are clearly to do with the interaction energy between molecules in the gas phase. 

Hull and Kitchener (2) measured the rate of deposition of 0.3- an-diameter polystyrene latex particles onto a rotating disk coated with a film of polyvinyl formaldehyde. In electrolytes of high ionic strength (where the double-layer repulsion is negligible), they found close agreement between experiments and the prediction of Levich s boundary-layer analysis (Eq. 3]), indicating that a diffusion boundary layer exists and that its thickness is large compared to the domain of van der Waais and hydrodynamic interactions. These are neces-... 

Table 2 Radii of the heavier aikaii metai cations (CN 6) and van der Waais radii of the pnictogen atoms as weii as bond iengths of the metai atoms to the pnictogen atoms of the j -bonded iigands (A)...

Figure 2 A cross section of a part of a macromolecule in space (atoms are shown as black circles) rolling probe, van der Waais, and accessible surface areas are indicated in the figure.

The nature of these two phases helps lo throw light on the melal-nonmetal transition. For example there has been much speculation that hydrogen molecules at suflicienlly high pressure, such as those occurring on the planet Jupiter, might undergo a transition to un "alkali metal The fundamental transition is one of a dramatic change of the van der Waais interactions of H2 molecules into metallic cohesion. ... 

In an engineering anaiysis, van der Waals area and volume are needed for silicon tetrachloride (SiCI4). Determine van der Waais area and volume for silicon tetrachloride. 

FIGURE 21.23 The van der Waals radii of the carbon and nitrogen atoms superimposed on an outiine of the moiecuiar structure of cyanuric triazide, C3N12, to show the voiume of space from which each moiecuie exciudes the others. Van der Waais forces in the moiecuiar crystai hoid the moiecuies in contact in a pattern that minimizes empty space. The thin white iines emphasize the 3-foid symmetry of the pattern. 

Conventional van der Waais Mixing Rules with a Single Binary Interaction Parameter (IPVDW Model)... 

This equation introduces the binary interaction parameter in a manner similar to that of eqn. (3.3.6) of the van der Waais one-lluid mixing rule. Next, the following modified form of the NRTL equation was used for the excess free-energy term ... 

Figure 14 Comparison of predicted and experimentai binary (S-L-V) phase trace for a naphthaiene-C02 system (—) R-K-S EOS with van der Waais mixing ruie, (— )R-K-S EOS with Panagiotopouios-Reid mixing ruie, (—) P-R EOS with van...

To increase the distance between the NH groups, the central —CHOH group of Structure 4.5 was replaced by a diol grouping, —CHOH—CHOH—. Inhibitors based on the new skeleton (Structure 4.7) were more powerful but their usefulness was limited by their poor solubility. The solvent-accessible surface of HIV protease with an inhibitor was examined (Figure 4.3 overleaf). This is done by positioning a solvent molecule so that its van der Waais surface is just in contact with the van der Waals surface of the active site. The solvent molecule is then allowed to move, keeping the two van der Waals surfaces just in contact. The path of the solvent molecule thus plots out a surface representing the closest approach of the solvent to the active site, known as the solvent-accessible surface. 

The most satisfactory account of this phenomenon is due to Mulliken, according to whom a complex (D, A) is formed from a donor (D) species and an acceptor (A) species. This complex can exist in two energy states, the difference in energy between the two being equal to the energy of a quantum at the maximum of the absorption band. In the ground state of the complex the binding between foe components h chiefly due let the Van der Waais... 

Van der Waais J D 1873 Over de continuiteit van den gas- en vioeistoftoestand PhD Thesis Sijthoff, Leiden (Engi. Transi. 1988 J. D. van der Waais On the Continuity of the Gaseous and Liquid States ed J S Rowiinson, voi. XiV of Studies in Statistical Mechanics ed J L Lebowitz (Amsterdam North-Hoiiand))... 

Van Konynenburg P H and Scott R L 1980 Criticai iines and phase equiiibria in van der Waais mixtures Phil Trans. R. Soc. 298 495-540... 

Nesbitt D J 1990 Dynamics of Poiyatomic van der Waais Compiexes ed N Haiberstadt and K C Janda (New York Pienum) pp 461-70... 

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