THE PHOSPHORESCENCE EXCITATION SPECTRUM OF JET COOLED $BENZALDEHYDE{^{1}}$

Address of Holtzclaw and Pratt: Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260. 1 Work supported by NSF (CHE-8402996).Author Institution:Recent experiments have demonstrated the feasibility of laser-induced phosphorescence experiments $\underline{via}$ direct pumping of the triplet state in a supersonic jet. We have extended the method in a probe of the $^{3}A^{\prime\prime} (n\pi^{\ast})$ system of the simplest aromatic carbonyl, benzaldehyde. Spectra at both low $(0.6 cm^{-1})$ and moderate $(0.06 cm^{-1})$ resolution have been obtained. Rotational and vibrational analyses of these data are in progress, the results of which will be given. Comparisons with theoretical and solid state work will be made allowing comment on vibronic coupling between the $^{3}n\pi^{\ast}$ state and a near degenerate $^{3}n\pi^{\ast}$ state as well as other issues