Accurate ab initio alkaline earth–helium pair potentials

Abstract

The well-tempered model core potentials were used to study interactions between the alkaline earth atoms (Be–Ba) and helium. Pair potentials, calculated at the CCSD(T) level of theory, were used in bound state calculations. A single-bound vibrational state was found for each complex. It was determined that Be and Mg would reside inside a helium nanodroplet, while a surface site is more likely for Ba. The Ca and Sr are in between the two extremes: they may occupy a deep dimple on the surface, resulting in a spectrum exhibiting characteristics of both surface and interior sites.