Group VI Molecular Photolytic Dissociation Studies Using Rare Gas Halide Lasers

Abstract

The need for short wavelength lasers with high energy storage capabilities to meet the demands of laser fusion research [1] has stimulated interest in the dipole forbidden ¹S_O→ ¹D₂, ³P₁ transitions of the Group VI elements (O, S, Se, Te). In particular, laser action has been observed [2] on both of these transitions in Se when the OCSe molecule is photodissociated by V.U.V. fluorescence emission from e⁻ beam pumped Xe ^*₂ . Because the rate for OCSe quenching of Se(¹S_O) by the reaction

$$\begin{gathered}{\text{Se (}}{}^1\mathop {\text{s}}\nolimits_{\text{O}} {\text{) + OCSE }} \to {\text{Se}}{}_2^* + {\text{CO }} \hfill \\\hfill\\\end{gathered}$$

((1))

is large and the quenching by other likely products is small [3], it is necessary to substantially dissociate (bleach) the parent OCSe by the V.U.V. flux. In this paper we report measurements of quenching rate constants and radiative lifetimes of excited states of Se₂, Se(¹S_O) production, and bleaching wave dynamics when Se₂ is pumped at a variety of wavelengths by a pulsed U.V. laser.