Role of energy fluxes in experiments on light-induced drift

Velocity-selective excitation of gas particles not only gives rise to a light-induced drift but also to energy fluxes. The dominant role is played by the energy flux of the optical excitation. It is shown that a change in the state of a gas due to the energy flux is negligible under typical conditions in experiments on the light-induced drift of molecules. The conditions necessary in experiments designed to observe energy fluxes in gases are formulated.