scholarly journals Anisotropic and isotropic triple-dipole dispersion energy coefficients for all three-body interactions involving He, Ne, Ar, Kr, Xe, H2, N2, and CO

1996 ◽  
Vol 74 (6) ◽  
pp. 1180-1186 ◽  
Author(s):  
Sean A.C. McDowell ◽  
Ashok Kumar ◽  
William J. Meath

Formulae for the computation of isotropic and anisotropic dipolar dispersion energy coefficients, for two-body and three-body interactions involving H2, N2, CO, and the rare gases, are presented in an average energy approximation. These coefficients are computed to within 1% of the reliable values for these coefficients, which are obtained by using the relevant dipole oscillator strength distributions, with the exception of a few that are recorded in tabular form. The input data required for these formulae are the isotropic and anisotropic polarizabilities and average energies for the interacting species. The results provide the first reliable anisotropic triple-dipole dispersion energy coefficients for interactions involving molecules. Key words: non-additive, anisotropic, interaction energies, triple-dipole dispersion energies.

1998 ◽  
Vol 76 (4) ◽  
pp. 483-489 ◽  
Author(s):  
Sean AC McDowell ◽  
W J Meath

Average energy approximations for the anisotropic triple-dipole dispersion energy coefficients are tested using reliable results for these coefficients, which are available for all interactions involving the rare gases, H2, N2, CO, O2, and NO. The original average energy approximation does not reproduce any of the anisotropic coefficients to within their estimated uncertainties. More recently derived average energy approximation formulae, requiring the isotropic and anisotropic polarizabilities and average energies for the interacting species as input, reproduce all but 69 of the 680 isotropic and anisotropic coefficients considered to within their estimated uncertainties.Key words: nonadditive, three-body interactions, dispersion energies.


2007 ◽  
Vol 85 (10) ◽  
pp. 724-737 ◽  
Author(s):  
A Kumar ◽  
B L Jhanwar ◽  
W Meath

A recommended isotropic dipole oscillator strength distribution (DOSD) has been constructed for the ethylene molecule through the use of quantum mechanical constraint techniques and experimental dipole oscillator strength (DOS) data; the DOS data employed are recent experimental results not available at the time of the original constrained DOSD analysis of this molecule. The constraints are furnished by molar refractivity data and the Thomas–Reiche–Kuhn sum rule. The DOSD is used to evaluate a variety of isotropic dipole oscillator strength sums, logarithmic dipole oscillator strength sums, and mean excitation energies for ethylene. Pseudo-DOSDs for this molecule, and for propene and 1–butene, which are based on an earlier constrained DOSD analysis for these molecules, are developed. They are used to obtain reliable results for the isotropic dipole–dipole dispersion-energy coefficients C6, for the interactions of the alkenes with each other and with 47 other species, and the triple-dipole dispersion-energy coefficients C9 for interactions involving any triple of molecules taken from ethylene, propene, and 1–butene.Key words: alkenes, dipole properties, pseudo-states, dipole–dipole and triple-dipole dispersion energies, long-range additive, non-additive interaction energies.


2012 ◽  
Vol 136 (10) ◽  
pp. 104104 ◽  
Author(s):  
Li-Yan Tang ◽  
Zong-Chao Yan ◽  
Ting-Yun Shi ◽  
James F. Babb ◽  
J. Mitroy

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