Thermal gasdynamic laser utilizing rotational transitions in hydrogen halides with energy transfer from H2 molecules

A theoretical analysis is made of the feasibility of developing an efficient thermal gasdynamic laser utilizing purely rotational transitions in the hydrogen halides HF, DF, HCl, and DCl with energy transfer from slowly relaxing (metastable) H₂, D₂, N₂, and CO₂ molecules. Two possible operating systems are proposed for such a laser: using only the rotational energy of the metastable molecules to excite the upper rotational levels of the hydrogen halides and using this method together with excitation due to vibrational-rotational relaxation of the hydrogen halides. Estimates are made of the maximum efficiency and specific laser energy for an H₂–HF system at an initial temperature of 300–4000 °K.