ROTATIONALLY RESOLVED ELECTRONIC SPECTRA OF 7-AZAINDOLE AND ITS ARGON COMPLEX: GEOMETRY AND TRANSITION MOMENT $ORIENTATION.^{a}$

$^{a}$ Work supported by NSF.Author Institution: Department of Chemistry, University of PittsburghRotationally resolved fluorescence excitation spectra of the $S_{1} (^{1}L_{b}) \leftarrow S_{0}$ origin bands of 7-azaindole and its Argon complex have been recorded and analyzed. The derived rotational parameters give information about the geometries of the two molecules in both electronic states. The Argon atom moves when the UV photon is absorbed because there are significant differences in the $S_{0}$ and $S_{1}$ intermolecular potential energy surfaces. A large rotation of $S_{1} \leftarrow S_{0}$ electronic transition moment of 7-azaindole relative to that of indole gives further information about this solvent reorganization