Even a weak interaction of molecules with phonons as they move under t
he influence of surface forces can strongly affect the distribution of
desorbed molecules. For the first time, a noncontradictory explanatio
n is found for experimental data on the associative desorption of hydr
ogen from the surface of the metal. The explanation is based on a kine
tic theory which incorporates a relaxation of an ensemble of desorbed
particles involving phonons.