THE THEORETICAL AND EXPERIMENTAL DISTINGUISHING OF PHOTOASSOCIATION INTO THE XECL(B) STATE

The spectrum of excitation into the XeCl(B) state is simulated by a pr ocedure rigorously taking into account the bound-bound (bb) and free-b ound (fb) transition contributions. The cross-sections for bb-absorpti on and photoassociation are calculated, and at their maxima, near lamb da = 308 nm, they amount to 1.2 x 10(-16) cm(2) and 1.4 x 10(-38) cm(5 ), respectively. An experimental approach is developed enabling the di stinguishing of fb-transition contributions by monitoring the excitati on into the XeCl(B) state in conditions when the equilibrium between n onexcited XeCl(X) molecules and free Xe and Cl atoms does not have tim e to be completed. The experimentally obtained ratio of intensities fo r the bb- and fb-transitions, amounting to 1.8-3.3, is in good agreeme nt with the calculations. These experiments enabled estimation of the rate constant for XeCl(X) state dissociation in bimolecular collisions with Xe atoms as being (3-6) x 10(-11) cm(3) s(-1).