Spin–orbit branching in Cl(2P) atoms produced by ultraviolet photodissociation of HCl

Abstract

The ultraviolet photodissociation of jet-cooled HCl molecules at 5 wavelengths in the range 201–210 nm has been investigated. Ground state hydrogen photofragments, H(²S), were detected using the H Rydberg atom time-of-flight (HRTOF) technique to obtain directly the relative yields of the available product channels: H(²S)+Cl(²P_3/2) and H(²S)+Cl(²P_1/2). The product branching fractions are reported and compared with recent experimental measurements and theoretical calculations. In addition, the two spin–orbit components of ground state chlorine photofragments formed by photolysis of HCl at 205.5 nm were monitored using (2+1) resonance enhanced multiphoton ionization (REMPI). The relative sensitivity of this detection method for Cl(²P_3/2) and Cl(²P_1/2) atoms is found by comparing the relative REMPI signal intensities with the product branching fraction determined by the HRTOF technique.