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Femtosecond Investigation of Photophysics of Intersystem Crossing in Terthiophene
Author(s) -
Yang JiPing,
Paa Wolfgang,
Hotzel Mario,
Rentsch Sabine
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.200000085
Subject(s) - intersystem crossing , chemistry , terthiophene , photoexcitation , photochemistry , internal conversion , triplet state , femtosecond , excited state , singlet fission , excitation , ultrafast laser spectroscopy , absorption band , spectroscopy , atomic physics , singlet state , laser , molecule , spectral line , optics , physics , organic chemistry , quantum mechanics , astronomy
Photophysics of ultrafast intersystem crossing and triplet yield in 2,2′:5′,2″ ‐terthiophene (3T) was investigated in dependence of excitation wavelength by means of femtosecond time‐resolved absorption/emission spectroscopy. Triplet generation yield was monitored by using the product of maximum and width of the photoinduced triplet absorption band near 460 nm. We found that triplets were generated by two different processes: (i) the well‐known intersystem crossing from the lowest vibrational S 1 state and (ii) ultrafast intersystem crossing from an intermediate state generated by photoexcitation. We discuss the probable formation mechanism and the lifetime of an intermediate state. The results suggest that this intermediate state is a nonplanar conformer within the S 1 manifold; it seems to be responsible for the high effective triplet generation.