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Excited singlet state time‐resolved Raman spectra of 4,4′‐bipyridine and quantum chemical analysis of resonance Raman intensities
Author(s) -
De Waele V.,
Buntinx G.,
Poizat O.,
Flament J.P.
Publication year - 2000
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/(sici)1097-4555(200004)31:4<275::aid-jrs539>3.0.co;2-g
Subject(s) - raman spectroscopy , resonance (particle physics) , chemistry , resonance raman spectroscopy , picosecond , singlet state , excited state , molecular physics , ab initio , raman scattering , ab initio quantum chemistry methods , analytical chemistry (journal) , atomic physics , laser , molecule , optics , physics , organic chemistry , chromatography
The low‐energy S 1 → S n electronic transitions of 4,4′‐bipyridine (44BPY) and the related resonance Raman intensities were analysed by ab initio calculation using the MCSCF method. This calculation is based on the previously optimized S 1 state geometry of 44BPY at the CIS level. The results are discussed in the light of experimental picosecond time‐resolved Raman measurements probed in resonance with two different S 1 → S n transitions and lead to a better insight in the electronic and structural properties of the 44BPY S 1 state. Although the calculated spectra are only in partial agreement with the measured intensities, the most characteristic resonance enhancement effects are correctly predicted. The asymmetric characteristic of the S 1 structure proposed previously is confirmed on this basis. A comparison of these resonance Raman effects with those characterizing two photoreduced transient radical species of 44BPY is also discussed. Copyright © 2000 John Wiley & Sons, Ltd.