Nonadiabatic sliding model for rearrangement collisions

Using Demkov's variational principle, the probability for electronic excitation is evaluated with the help of optimized basis states, which allow for a continuous transition from an atomic to a molecular description. The inclusion of cosliding translational factors provides an extension to transfer processes. Calculations are performed for radiative electron capture (REC) of a target K electron in the collision systems ¹⁶O{→}¹²C and ³²S{→}²⁰Ne. It is shown that even for fast collisions, an atomic description is only applicable in the REC peak region, while molecular effects have to be included in the tails.