Abstract
A series of LCAO‐MO‐SCF calculations, using various basis sets of Gaussian‐type functions, has been made in order to study the effects of p, d, and f polarization functions for a 10‐electron isoelectronic series of oxygen hydrides and for an 18‐electron isoelectronic series of sulfur hydrides. Conclusions from these results suggest that meaningful proton affinities cannot be calculated without the inclusion of a d function on the heavy atom and a p function on the hydrogen atoms.