Chemical-Laser-Induced Isotopically Selective Reaction of HCl

Abstract

A pulsed HCl chemical laser is used to excite HCl molecules vibrationally in the presence of Br atoms in a discharge-flow reactor. The rate of the reaction $\mathrm{Br}+\mathrm{HCl}(v)\ensuremath{\rightarrow}\mathrm{HBR}+\mathrm{Cl}$ increases by a factor of ${10}^{11}$ at room temperature if $\mathrm{HCl}(v=0)$ is excited into $v=2$. Excitation occurs predominantly for ${\mathrm{H}}^{35}$Cl. Cl atoms generated by the laser-stimulated reaction react with ${\mathrm{Br}}_{2}$ to form BrCl, which is detected by time-resolved mass spectrometry and shows an enrichment of $^{35}\mathrm{Cl}$ (90% $^{35}\mathrm{Cl}$).