MOLECULAR ION EMISSION FROM PHOTOIONIZATION

Author Institution: Department of Chemistry, Yale UniversityThe advantages of using photoionization as a source for molecular ion emission spectra are discussed. Spectra of $HBr^{+} (A^{2}\Sigma^{+} \rightarrow X^{2}\Pi)$ and $CS_{2}^{+} (B^{2}\Sigma_{u}^{+} \rightarrow X^{2}\Pi_{g}$ and $A^{2}\Pi_{u} \rightarrow X^{2}\Pi_{g})$ excited with the helium 584 {\AA} resonance line have been observed at 20 {\AA} resolution with a high aperture monochromator and photon counting. Since excited state population rates in such sources are calculable from photoelectron spectra, non-radiative processes depleting these states can be studied; predissociation of $HBr^ + A^{2}\Sigma^{+}$ is discussed in this context