l-changing collision of a high-Rydberg atom with a polar molecule

Cross sections of the title process are theoretically evaluated to be of order of 10^-14 - 10^-11 cm², using the model in which an excited Rydberg electron behaves as if it were "free" and slow, with interaction between the excited electron and a polar molecule playing a decisive role. The n dependence of the cross section shows a sharp peak as the energy defect becomes small.