Perturbation of highly excited states of an atom by the field of a neutral particle

Rydberg atom A** states perturbed by the force field of a neutral atom B are examined. The problem is reduced to studying the wave functions of the composite system and elucidating their fundamental differences from the Rydberg wave functions. The wave function of the Rydberg atom A**-atom B system is constructed using the finite-radius potential method with consideration for the short- and long-range interactions of the weakly bound Rydberg electron with the perturbing particle. The Na**-He system is considered as an example.