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Femtosecond S 3 →S 1 Conversion and Structural Reorganisation of trans ‐3‐Phenylprop‐2‐enaldehyde and Derivatives in Solution
Author(s) -
Lustres J. L. Pérez,
Farztdinov Vadim M.,
Kovalenko Sergey A.
Publication year - 2005
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200400518
Subject(s) - excited state , picosecond , intramolecular force , ultrafast laser spectroscopy , ground state , relaxation (psychology) , chemistry , spectroscopy , supercontinuum , spectral line , photochemistry , molecular physics , atomic physics , stereochemistry , physics , laser , optics , psychology , social psychology , quantum mechanics , organic chemistry , astronomy , photonic crystal fiber , fiber
Photoinduced excited‐state relaxation of trans ‐3‐phenylprop‐2‐enaldehyde (cinnamaldehyde) and three derivatives was studied in hexane and acetonitrile with the pump–supercontinuum‐probe technique. Transient spectra were measured with 50 fs resolution in the range 260–660 nm after S 3 ←S 0 excitation at 288 nm. The early spectra reveal an ultrafast, 0.1–0.5 ps, interchange of intensity between two excited‐state absorption (ESA) bands followed by a ≈3 ps decay of ESA. This behaviour is interpreted with the help of semiempirical calculations, which indicate that the sub‐picosecond evolution is consistent with S 3 →S 1 excited‐state relaxation while the picosecond decay should be due to a structural intramolecular rearrangement. The latter may consist of a twist of the phenyl ring and rotation around the CC bond to a perpendicular conformation which corresponds to the global energy minimum in the S 1 state and serves as source for trans and cis isomers in the ground state.