Intermolecular potential for vibrationally excited CH3F measured by light-induced drift

From changes in the diffusion coefficient upon vibrational excitation of CH3F in He, Ne, Ar, Kr, and Xe, as measured by light-induced drift, the intermolecular potential between two vibrationally excited CH3F molecules is determined on the basis of simple combination rules. The main effect of vibrational excitation is found to be an increase in potential well depth by 3%.