POST-ADIABATIC APPROACH TO ATOMIC AND MOLECULAR PROCESSES - THE VAN-DER-WAALS INTERACTIONS OF SOME OPEN-SHELL SYSTEMS

Various properties of post-adiabatic representations of multichannel Schrodinger equations are described in the general context of adiabatic and classical path approximations as used in atomic and molecular physics. The van der Waals interactions of fluorine, chlorine, and oxygen atoms with rare gases, hydrogen, methane, and hydrogen halides are considered: it is found that in some of these systems, the first-order post-adiabatic scheme exhibits a smaller coupling than the adiabatic representation, thus providing an appropriate choice of the basis functions for a decoupling approximation.