General anharmonic force constants of nitrous oxide

Abstract

Nineteen force constants of the most general quartic force field have been determined for the nitrous oxide molecule from the spectroscopic data on N 2 14O 16, N 15N 14O 16, N 2 15O 16, and N 2 15O 18 along with four third-order parameters, λ 1, λ 2, λ 3, and δ which appear in the Fermi coupling off-diagonal matrix elements. It has been shown that the stretching potential of N 2O is well represented by a Morse type potential and there is a close relationship between the principal stretching force constants for a given bond and those of the corresponding diatomic molecule. An effort has also been made to correlate the principal stretching force constants with the corresponding bond dissociation energies. From these force constants, the potential energy contour maps for N 2O are drawn. The vibrational constants of N 2 14O 16 have been reanalyzed by applying the method originally developed for the vibrational analysis of carbon dioxide by Amat and Pimbert. The vibrational constants obtained are compared with those derived from the anharmonic force constants.