Atom–polyatomic collisions: A many-body approach

We present an approach to atom–polyatomic collisions that takes into account the quantum nature of the polyatomic motion, but avoids expansions in target states by instead describing the target as a many-atom system. Following a discussion of interaction potentials, kinematics, and the general scattering formalism, we introduce two basic assumptions that lead to useful expressions for differential cross sections. The treatment is specialized to quasielastic scattering, of interest in the interpretation of experiments. This study shows that the atomic-pair correlation functions of the target play a central role in determining collisional energy and momentum transfer.