ROLE OF ELECTRON DISSOCIATIVE ATTACHMENT AND IMPACT DISSOCIATION OF HCL IN XECL LASERS.

A computer model of electron-beam pumped XeCl laser mixtures has been developed that uses a time-dependent Boltzmann solution for the secondary electron distribution. The model has been improved by including HCl vibration levels for v greater than 2 and additional HCl chemistry. For the pump conditions of the electron density and HCl burnup measurements, the model predicts that the secondary electron distribution is significantly non-Maxwellian. It also supports the conclusion that the initial rapid increase of the electron density at the beginning of the pump pulse is due to the finite vibrational excitation time of HCl. The model and data also indicate that electron dissociative attachment by itself cannot adequately explain the increase in the electron density toward the end of the pulse.