Abstract
The decay of the 1s5 metastable state of xenon has been measured by means of an absorption technique in the afterglow of a pulsed DC discharge. At the same time the decay of excited Xe2* molecules has been measured by monitoring the ultraviolet continuum radiation. It is shown that these excited molecules are formed in two-body and three-body collisions between metastable 1s5 atoms and ground state atoms. The rate coefficient for de-excitation of 1s5 state by two-body collisions is determined as 35*10-16 cm3 s-1 and and the rate coefficient for de-excitation by three-body collisions as 8.55*10-32 cm6 s-1. The diffusion coefficient of Xe(1s5) in Xe is DM=52*1016 cm-1 s-1.