Contraction of Gaussian basis sets for second-row diatomic molecules

Abstract We have augmented the extended Gaussian basis sets (GBSs) (18s13p) previously generated for second-row atoms with an improved generator coordinate Hartree–Fock (HF) method up to (23s13p). These new extended basis sets are then contracted to [8s5p] and [8s6p] by a standard procedure; the latter, in combination with the previously contracted Gaussian basis set [6s4p] for the first-row atoms are enriched with polarization functions. These contracted basis sets are applied for the second-row diatomic molecules AlF, SiO, PN, SC, ClB and P 2 . The total and highest occupied molecular orbital HF energies are calculated and compared with the corresponding numerical HF (NHF) values. The dipole moments and bond lengths are calculated at the HF, MP2, MP4, CISD, and DFT levels, as well as the harmonic vibrational frequencies (HF, MP2, MP4, DFT levels) and the dissociation energies (MP2, MP4, DFT levels) and compared with the corresponding experimental values and with those obtained using other contracted GBSs and NHF calculations.