PSEUDOSPECTRAL HARTREE-FOCK THEORY - APPLICATIONS AND ALGORITHMIC IMPROVEMENTS

Several additions to the pseudospectral Hartree-Fock theory are described, including a localized least-squares procedure, various numerical cutoff algorithms, and calculation of all integrals in the diatomic frame. This pseudospectral method is tested on 23 molecules, ranging in size from two to twenty atoms (200 6-31G** basis functions). A direct comparison of accuracy and computational efficiency is made with the conventional electronic structure programs GAMESS, GRADSCF, GAUSSIAN 86, and GAUSSIAN 88. The pseudospectral code is shown to be up to nine times faster than any of the above programs for the molecules tested here; moreover, this timing advantage increases with molecular size, suggesting that ab initio calculations may soon be possible on large systems not accessible by the Roothaan-Hall procedure. © 1990 American Institute of Physics.