Formation and decay of Hg2 excimers in Hg--Ar mixtures

The formation and decay of Hg2 molecules in their 31/subu/ and 30/subu/- states, produced in Hg-Ar mixtures irradiated with 2537-A Hg resonance radiation, has been investigated by the method of delayed coincidences. The mixtures which consisted of Hg vapor at a pressure of about 1 Torr and Ar at pressures of 45--720 Torr and which were contained in a quartz fluorescence cell, were excited with pulses of light, and the decay spectra of the 3350- and 4850-A molecular fluorescent bands were studied in relation to Ar pressure. Analysis of the decays indicates that the effective cross sections for 31/subu/ - 30/subu/- mixing, induced in Hg2-Ar collisions are of the same order as the Hg2-N2 mixing cross sections, leading to the conclusion that the 4850-A band is emitted mainly by 30/subu/- molecules in high vibrational states