Highly accurate Gaussian basis sets for some 14‐electron diatomic systems*

A molecular improved generator coordinate Hartree–Fock (HF) method is used to generate highly accurate Gaussian basis sets for N2, BF, CO, NO+, and CN−. For these molecular systems, sequences of basis sets of atom-centred Gaussian-type functions are employed to explore the accuracy achieved with this method. Our ground state HF total energies are lower than the corresponding ones calculated with other basis sets of primitive Gaussian-type functions reported in the literature. For the molecular systems here studied, the differences between the HF total energy results obtained with our largest basis sets and with a numerical HF method are equals to 38.2, 13.9, 33.0, 76.7, and 55.7 μhartree for N2, BF, CO, NO+, and CN−, respectively. We have also calculated the multipole electric moments and compare them with the corresponding experimental values and with results computed by other approaches. © 2002 John Wiley & Sons, Inc. Int J Quantum Chem, 2002