Far infrared chemical lasers. Technical progress report No. 6, September 1, 1979-August 31, 1980

Abstract

Some preliminary experiments in gas laser research are discussed. A new technique for measuring the linewidth of many high J,K rotational lines is presented. The method utilized the Stark effect on optically-pumped molecular gas lasers. Formulas are given for calculating linewidths from experimentally measured electric field strengths. Pure rotational laser oscillation has been observed in HF following flash photolysis of various mixtures of trifluoromethyl halide, acetylenic compound and argon in the ratio of 1:1:100. The mixed systems show laser intensity at lower rotational levels than could be explained by simple V ..-->.. R collision induced mechanisms (as in the case of CH/sub 2/CF/sub 2/). Further, the intensities in these anomalously low rotational levels appear to be a function of the identity of the electronically excited halide (I* or Br*) produced photolytically. A computer simulation model has been constructed which relaxes nascent HF through V ..-->.. R transfer (formed vibrationally and rotationally excited by elimination) but incorporates an additional pumping mechanism, that of quenching of I* or Br* by these relaxing HF molecules. Most of the experimentally observed laser intensities are explained on the basis of this new pumping mechanism. The observations of intense, amplified spontaneous emission on fifteen far infrared lines from flashlamp pumped H/sub 2/O vapor in the 0.010 to 0.080 torr pressure range is described and explained. A mechanism based on direct optical pumping and collisional redistribution between resonance perturbed levels is presented. The mechanism accounts for experimental dependence of the superfluorescent emissions on pressure and flashlamp energy. Progress is also reported on some preliminary experiments with flashlamp pumping of three new molecules, H/sub 2/CO, NH/sub 3/, and H/sub 2/S.