Three-body alkali-noble-gas interactions and secondary satellites

Abstract

The interaction between an alkali atom and several noble-gas perturbers is considered. Whereas in the ground state of the system, the total potential energy is very nearly the sum of two-body interactions, the lowest excited state splits into three surfaces which are generally non-additive, i.e. which cannot generally be written as the sum of two-body interactions. However, with a minimal atomic basis the three-body interactions can be expressed in terms of the two-body ones. Some consequences are discussed for secondary satellites in the wings of alkali lines broadened by noble-gas perturbers.