In the flash photolysis of Me2Hg, approx. 85% of the Me radicals are produced in excited states. From a study of the relaxation rate in various gases, i.e. He, Ar, O2, it is evident that the free radicals are excited vibrationally and it is suggested that the rate is controlled by the out-of-plane bending mode. There was no dependence on pressure at >=3 torr for the combination of the Me radicals.