HIGH RESOLUTION ELECTRONIC SPECTROSCOPY OF INDOLE AND INDOLE ($H_{2}O$) IN A MOLECULAR BEAM: EVIDENCE FOR $^{1}L_{a}$-AND $^{1}L_{b}$-STATE $MIXING.^{a}$
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Date
1997
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Ohio State University
Abstract
The electronic spectrum of indole and its sensitivity to the surrounding environment continues to attract much $attention.^{b}$ We report here studies of the rotationally resolved electronic spectra of several vibronic bands of indole and indole ($H_{2}O$) in a molecular beam, up to an energy of $990 cm^{-1}$ above the electronic origin of the ${^{1}}L_{b}$ state at $35231.525 cm^{-1} (\approx 284 nm)$. We find, as did Berden, et $al.^{c}$ for the $0^{0}_{0}$ band, that the vibronic bands exhibit ``anomalous” line intensities, evidencing axis tilting on $S_{1}$ excitation. The degree of tilt is different for different bands, showing that the $S_{1}\leftarrow S_{0}$ optical transition moment orientations are also different. We derive from careful analyses of these data information about $^{1}L_{a}-^{1}L_{b}$ state mixing in the isolated molecule and its dependence on displacements along different vibrational coordinates. We also show that complexation of indole with one water molecule significantly influences the degree of this mixing.
Description
$^{a}$Work supported by NSF(CHE-9617208). $^{b}$Y. Huang and M. Sulkes, {J. Phys. Chem}. 100(1996), 16479 and references therein. $^{c}$G. Berden, W. L. Meerts, and E. Jalviste, {J. Chem. Phys}. 103(1995), 9596
Author Institution: Institut f\""ur Chemie und Elektrochemie, Heinrich-Heine-Universit\""at; Department of Chemistry, University of Pittsburgh
Author Institution: Institut f\""ur Chemie und Elektrochemie, Heinrich-Heine-Universit\""at; Department of Chemistry, University of Pittsburgh