THE 614 nm SUPERSONIC JET SPECTRUM OF THIOACETALDEHYDE

Author Institution: Department of Chemistry, Brock University, St. Catharines; Department of Chemistry, The University of Kentucky; Instituto de Estructura de la Materia, Consejo Superior de Investigaciones; Escuela Universitaria de Informatica, Universidad de Castilla - La ManchaThe $S_{0} - T_{1}$ electronic transition in $CH_{3}CHS, CD_{3}CHS, CH_{3}CDS, CD_{3}CDS$ has been observed in a continuous supersonic pyrolysis jet as a laser phosphorescence excitation spectrum. The potential surface for the torsional - wagging internal coordinates were mapped out with ab initio molecular orbital calculations with a $6-31G^{*}$ basis in which the structural parameters were fully relaxed. The kinetic and potential energy data points were fitted to analytical double fourier expansions. These were incorporated into a two - dimensional Hamiltonian matrix in the torsion and wagging coordinates and symmetrized by the $G_{6}$ point group and solved for the energies and wavefunctions. The spectrum calculated from the the frequencies and Franck - Condon factors was fitted to the observed ``hot” and cold band spectra and refinements were made to the potential surface."