Dependence of light-induced drift of CH3F molecules on the radiation frequency

Measurements were made of the dependence of the light-induced drift of ¹³CH₃F molecules on the frequency of the exciting radiation over a range of ~200 MHz. A waveguide CO₂ laser was used as the excitation source. A change in the sign of the effect was recorded on passing through the center of the absorption line. The results of the measurements were found to be in good agreement with the calculated dependence of the effect as obtained using a model of strong collisions.