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ALLAN L. L. EAST, I. DECHENE, W. SIEBRAND, M. Z. ZGIERSKI, P. R. BUNKER, Steacie Institute of Molecular Science, National Research Council, Ottawa, Ontario K1A 0R6, Canada; P. JENSEN, FB 9-Theoretische Chemie, Bergische Universitat-Gesamthochschule Wuppertal, D-42097 Wuppertal, Germany.
Experimental measurements have been reported the S1-S0 fluorescence excitation spectrum of toluene1 which reveal forbidden bands corresponding to excited levels of the methyl internal rotation mode. We present theoretical predictions of the rotational fine structure of these bands, incorporating \sl ab initio and least-squares-fitted geometrical structures for the S0 and S1 states. We particularly consider the coupling of overall and internal rotation, and the direct calculation of individual rovibronic line intensities.
1 R. A. Walker, E. Richard, K.-T. Lu, E. L. Sibert III, and J. C. Weisshaar, J. Chem. Phys. 102 (1995) p. 8718, and references therein.