How Important are High-Level ab initio Treatments for the Interaction Dipole Moment and Polarizability of Hene?

We report calculations of the interaction dipole moment and polarizability for the HeNe heterodiatom. Our results are extracted from finite-field Møller-Plesset perturbation theory and coupled cluster calculations with a large, flexible Gaussian-type basis set. At post-Hartree-Fock level, the interaction dipole moment is method-sensitive for relatively short internuclear separations R/a0 while the interaction polarizability becomes rapidly method-insensitive for R/a0 > 2.5.

AIM study on the transferability of the oxygen atom in linear ethers

The integrated values of the electron population, electron energy, nucleus–electron potential energy interaction, dipole moment and volume of the oxygen atoms, and the main properties of the O—C bond critical points, were determined by employing the theory of atoms in molecules and 6-31++G**//6-31G* wave functions for a series of 25 unbranched alkyl monoethers. These results were used to assess the degree of approximate transferability of the oxygen atom along this series in terms of the particular alkyl radicals bonded to it. It has been found that a set of six different oxygen atoms is necessary to classify all the computed values. It can be established that the oxygen atoms bonded to propyl and larger radicals can be treated, in practice, as a transferable fragment, while those bonded to at least one smaller radical are specific. Though the total HF energy and the available experimental heats of formation are well fitted by a traditional additivity scheme that distinguishes only among O, CH2, and CH3 units, it has been found that the energy properties are influenced by the size of the molecule.Key words: transferability, AIM theory, ethers.

Infrared absorption in doped rare gas crystals

Molecular dynamics calculations based upon realistic pair potentials plus three body forces are used to investigate the properties of solid argon doped wth 2% krypton. The infrared absorption, which is computed using an expression for the interaction dipole moment derived from gas phase data, agrees well with experimental data.