Spectral and energy characteristics of a pulsed hydrogen fluoride laser and rotational relaxation of HF molecules

The spectrotemporal and energy characteristics of the radiation of a pulsed chemical H-2-F-2 laser were calculated on the basis of a multilevel model taking into account the nonequilibrium population of the rotational levels, and were compared with experimental data. The theoretical model took into account the stimulated emission of radiation as a result of the v, j -1 --> v - 1, j transitions (v = 1 - 6 and j = 4 - 12) in the HF molecule. The ro tational relaxation fate constants of the HF molecule were varied in the ca lculations. Comparison of the calculated and experimental spectral characte ristics of the laser radiation indicates that the rate of the rotational tr ansitions involving high (j = 10-12) rotational sublevels of HF is insuffic ient, leading to an appreciable reduction in the energy of the output radia tion for lines with such values of j, compared with lines characterised by j = 7, 8.