Intermolecular interactions using small basis sets: Perturbation theory calculations avoiding basis set superposition error

Abstract

As preliminary numerical examples, we report some calculations on intermolecular interactions using a new method of perturbation theory introduced recently. The He…He, LiH…LiH and water—water interactions are studied with small basis sets. The essential feature of the method is that it eliminates basis set superposition errors without any a posteriori collection. Within the range of applicability of the perturbational treatment, the results may be superior to standard vibrational calculations which suffer from large basis set superposition errors.