Applications of a simple molecular wavefunction. Part 15.—Spectroscopic constants of selected first-row diatomic hydride molecules

Abstract

The FSGO method and its extension to include contracted basis sets of Gaussians to describe each electron pair are used to calculate spectroscopic properties of selected diatomic hydride molecules of first-row atoms. Increasing the size of the basis sets leads to a rapid improvement in the values of calculated properties. This is particularly noticeable in the case of bond lengths (and related rotational constants) where the results obtained at the triple Gaussian level of expansion compare favourably with those of the HF-limit SCF–LCAO–MO calculations. Properties associated with vibronic motion are calculated less satisfactorily.