The importance of diffuse f functions for transition metals

Abstract

The importance of a diffuse f function for determining the dissociation energy (D_e) of Cu₂ and the ³F–³D energy separation in Ni atom is investigated. It is found that the diffuse f contributes at most 0.05 eV to the D_e of Cu₂ when added to a basis containing tight f functions and a flexibly contracted d basis. The diffuse f function is found to decrease the ³F–³D separation in Ni, but by substantially less than the tight f functions.