Rotational quenching of dipole-dipole interaction

Abstract

Experiments based upon light-induced drift have yielded direct information on the rotational-state dependence of intermolecular interactions. Data were obtained for the change in collision rate ν upon rovibrational (J, v) excitation of HF in Ar, H2, HCl, CH4 and CH3F. It is found that J and v have independent influences on ν. For the dipole-dipole cases, ν decreases by up to 40% as JHF increases from 0 to 6. This is attributed to the increased averaging-out of the dipolar potential. A theoretical treatment based upon the first Born approximation yields good agreement with the HF-HCl data.