Systematic Truncation of a Distributed Universal Even-Tempered Basis Set of Gaussian Functions: an Application to the Ground State of the BF Molecule

Abstract

Systematic sequences of distributed universal even-tempered basis sets of Gaussian functions have been shown to support an accuracy approaching the sub-μHartree level for the total Hartree-Fock energies for diatomic molecules containing first row atoms. They have also been shown to support high precision correlation treatments. Furthermore, the use of a similar approach for systems containing heavy atoms and for polyatomic molecules has been demonstrated. In this paper, systematic truncation of basis sets developed in this fashion is explored. An application to the Hartree-Fock ground state of the BF molecule at its equilibrium geometry is described. The parent distributed universal basis set, which contains a total of 623 primitive Gaussian functions, is truncated by systematically removing those basis functions for which the magnitude of the elements of the orbital expansion coefficient vector are less than some small τ for all occupied orbitals. The effects of truncation on the description of electron correlation effects using second order many-body perturbation theory is also explored.