Chemical Lasers from the Reactions of ClF and ClF3 with H2 and CH4: A Possible Chain-Branching Chemical Laser

Both HF and HCl chemical laser emission have been observed from the flash photolysis of $\mathrm{ClF}–{\mathrm{H}}_2\mathrm{–Ar}$ and ${\mathrm{ClF}}_3{\mathrm{–H}}_2\mathrm{–Ar}$ mixtures. In contrast, only HF laser emission is produced by flash photolysis of $\mathrm{ClF}–{\mathrm{CH}}_4\mathrm{–Ar}$ or ${\mathrm{ClF}}_3{\mathrm{–CH}}_4\mathrm{–Ar}$ mixtures. For the $\mathrm{ClF}–{\mathrm{H}}_2$ system, the presence of 3→2 HF transitions and the appearance of HCl transitions show that the $\mathrm{H}+\mathrm{ClF}$ reaction divides to form very roughly equal amounts of HCl and HF. For HCl, equal–gain temperature measurements place k₂/k₁ in the range 1.2–3.8. The ${\mathrm{ClF}}_3{\mathrm{–H}}_2$ chemical laser is extremely intense, but it displays much lower vibrational excitation of HF than that of $\mathrm{ClF}–{\mathrm{H}}_2$ or of ${\mathrm{ClF}}_3{\mathrm{–CH}}_4$ . There is evidence that chain‐branching reactions occur, which enhances the potentiality of the ${\mathrm{ClF}}_3{\mathrm{–H}}_2$ system as a possible high‐power, continuously operating chemical laser.