ANHARMONIC VIBRATIONAL ANALYSES OF AB INITIO POTENTIAL ENERGY SURFACES FOR FORMALDEHYDE
Loading...
Date
1984
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
A computer program for calculating vibrational-rotational spectroscopic constants for polyatomic molecules has been developed. Calculated energies at chosen geometries are fitted to a polynomial function of the internal coordinates which is used in a normal mode analysis. The energy surface is re-expanded as a power series in the normal coordinates with the resulting force constants then employed to incorporate the effects of anharmonicity in calculating spectroscopic constants. Formaldehyde and its deuterated isomers was examined using ab initio techniques at the self-consistent field, M\""{o}ller-Plesset perturbation theory, and configuration interaction levels of approximation. Harmonic frequencies are in good agreement with experimentally derived values for the most accurate surfaces and anharmonic spectroscopic constants compare well with values recently derived from spectral data.
Description
Author Institution: Theoretical Chemistry Group, Chemistry Division, Argonne National Laboratory; Department of Chemistry, Chemical Engineering