ENERGY-TRANSFER IN MERCURY-VAPOR FOLLOWING LASER EXCITATION OF THE 7(1)S-0 STATE BY 2-PHOTON ABSORPTION

After excitation of the 7S-1(0) mercury state by two photon absorption of a laser radiation at 313 nm the time integrated intensities of the 407.8 (I0) and 404.7 nm (I1) lines emitted from the 7S-1(0) and 7S-3( 1) states were determined as functions of the pump laser intensity, I, and mercury pressure. At high pump laser intensities I0 and I1 do not follow anymore a quadratic law in I, I0 weakens to I(n<2) while, in c ontrast, I1 increases to I(n>2). The time evolutions of the population s of these 7S-1(0), 7S-3(1) states and of the 6P-1(1), 6P-3(0,1,2) sta tes were determined. The set of experimental results is well reproduce d by introducing collisions of two Hg(6P) atoms as well as two Hg(7S-1 (0)) collisions. Effects of these collisions are discussed.