Gaussian basis sets for some polyatomic two-heavy-atom hydrides

Abstract

Gaussian basis sets have been generated with an improved generator coordinate Hartree-Fock (HF) method. These have been contracted and enriched with polarization functions. For the molecules, C₂H₂, C₂H₄, C₂H₆, N₂H₂, N₂H₄, H₂O₂, Si₂H₂, P₂H₄ and H₂S₂, the ground state HF total energies have been calculated using our and 6-31 G* basis sets. At the HF and MP₂ levels, equilibrium geometries and harmonic vibrational frequencies have been calculated and compared with the corresponding experimental results and with results calculated with the 6-31 G* bas is sets. At the MP2 level, significant improvements are noted in these results, and the mean absolute (percentage) deviations from experimental bond length, bond angle, and vibrational frequency are 0.008Å, 1.6°, and 2.61 %, respectively.