Enrico Clementi

TL;DR: In this paper, the potential energy surface of the 1A'1 ground state of H+3 has been calculated at 69 different points with the Hylleraas configuration interaction method using 13s3p1d Cartesian Gaussian basis functions.

TL;DR: In this paper, the Hartree-Fock (HF) model is shown to be a good model for many-electron problems, and it can provide an alternative to popular proposals from density functional theory, and should prepare the ground for generalized HF models.

Abstract: In order to explain the observed changes in the vibrational spectra of formic acid from monomeric to cyclic dimeric form the SCF Hartree–Fock method has been applied to calculate minimum energy geometries, quadratic force constants, and net atomic charges. The set of ab initio quadratic force constants turns out to be acceptable and accounts for the observed vibrational changes. The ab initio interaction force constant between carbonyl stretching motions for the dimer accounts for what is considered to be an unusually large observed splitting of the C=O stretching frequencies in carboxylic acid dimers. Calculations suggest that such a large splitting originates from a dynamical charge transfer through the hydrogen bond. The possible existence of this phenomenon should in general be considered when dealing with the vibrational properties of hydrogen bonded systems.

TL;DR: In this paper, the Hartree-Fock potential for the water Dimer was used as a test case for the structure of liquid water in a single molecule, and the results showed that the potential of the potential was higher than the Hartrees-Focking potential.

TL;DR: Monte Carlo simulations for a methanol molecule enclosed in a cluster of 198 water molecules are presented in this paper, where the water structure near the methyl group is similar to that reported for methane.