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Picosecond–nanosecond time‐resolved resonance Raman study of the structure and dynamics of the excited states of 5‐dibenzosuberene derivatives
Author(s) -
Sakai Makoto,
Mizuno Misao,
Takahashi Hiroaki
Publication year - 1998
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(199810/11)29:10/11<919::aid-jrs333>3.0.co;2-p
Subject(s) - raman spectroscopy , picosecond , nanosecond , chemistry , resonance (particle physics) , excited state , relaxation (psychology) , resonance raman spectroscopy , absorption spectroscopy , absorption (acoustics) , spectroscopy , vibrational energy relaxation , photochemistry , nuclear magnetic resonance , analytical chemistry (journal) , molecule , materials science , atomic physics , laser , optics , physics , psychology , social psychology , organic chemistry , quantum mechanics , chromatography , composite material
Structures and dynamics of the excited electronic states,S 1 and T 1 , and cation radicalR + • of 5‐dibenzosuberene (DBCH) and itsderivatives were investigated in the picosecond–nanosecond timedomain using time‐resolved resonance Raman spectroscopy with the aidof time‐resolved absorption spectroscopy. For both 5‐dibenzosubereneand 5‐dibenzosuberenol (DBCH‐5‐ol) the effect of vibrational coolingor vibrational relaxation in S 1 was detected in both theRaman and absorption spectra in the 0–40 ps time region; thetime constant of this effect was estimated to be about 13 ps for bothDBCH and DBCH‐5‐ol. The expected conformational change in theS 1 state of DBCH‐5‐ol was not clearly observed in theresonance Raman spectra. It was observed, however, that the centralethylenic C=C bond was weakened considerably in S 1 ,but the degree of the weakening was considerably less than that ofT 1 and was very similar to that ofR + • . The dynamics of S 1 of5‐dibenzosuberenone were complicated, possibly owing to the existenceof a carbonyl group, and are not discussed. © 1998 John Wiley& Sons, Ltd.