MEASUREMENT OF EXCITED STATE DIPOLE MOMENTS OF 7-AZAINDOLE IN THE GAS PHASE.$_{a}$

$^{a}$Work supported by NSF.Author Institution: Department of Chemistry, University of PittsburghThe rotationally resolved $S_{1} \leftarrow S_{0}$ fluorescence excitation spectrum of 7-azaindole has been obtained in the presence of an external electric field. The Stark effect on the rotational energy levels allows us to accurately determine the values for each component of the dipole moment in both electronic states. The magnitudes of dipole moment components are $\mu_{a} (S_{0}) = 1.45 \pm 0.01 D, \mu_{b} (S_{0}) = 0.65 \pm 0.06 D$ and $\mu_{a} (S_{1}) = 2.23 \pm 0.01 D, \mu_{b} (S_{1}) = 0.55 \pm 0.07 D$. The large increase in $\mu_{a}$ is a result of changes in the electron distribution in the $S_{1}$ state. A detailed discussion of these changes will be given