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Ultrafast Charge Transfer Studied by Femtosecond IR‐Spectroscopy and ab Initio Calculations
Author(s) -
Kummrow Andreas,
Dreyer Jens,
Chudoba Christian,
Stenger Jens,
Theodorus Erik,
Nibbering Johannes,
Elsaesser Thomas
Publication year - 2000
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.200000099
Subject(s) - chemistry , femtosecond , ultrashort pulse , charge (physics) , ab initio , femtochemistry , spectroscopy , ab initio quantum chemistry methods , chemical physics , computational chemistry , atomic physics , molecular physics , laser , molecule , organic chemistry , optics , quantum mechanics , physics
Femtosecond vibrational spectroscopy is a versatile method to monitor excited state dynamics evolving in photochemical reactions. Applying high‐level calculations to analyze infrared absorption spectra allows to elucidate molecular structures of the transient compounds and to assign normal modes to the absorption lines. Striking differences in the experimental vibrational pattern of the locally excited states of 4‐(dimethylamino)benzonitrile (DMABN) and 4‐aminobenzonitrile (ABN) (dissolved in acetonitrile) are explained on the basis of planar and pyramidal structures obtained from ab initio complete‐active‐space self‐consistent‐field (CASSCF) calculations, giving evidence for a strong sensitivity of the molecular structure on modest changes in the substituents. Different models for the charge transfer state of DMABN are evaluated.