Electronic spectrum of a photochromic diarylethene derivative in a supersonic free jet. Internal conversion from S2(1B) to S1(2A)
作者:Nobuyuki Tanaka、Chie Okabe、Kenji Sakota、Tuyoshi Fukaminato、Tsuyoshi Kawai、Masahiro Irie、Alexander Goldberg、Shinichirou Nakamura、Hiroshi Sekiya
DOI:10.1016/s0022-2860(02)00316-2
日期:2002.10
The fluorescence excitation and dispersed fluorescence spectra of the open-ring isomer of 1,2-bis(3-methyl-2-thienyl)perfluorocyclopentene have been measured in a supersonic free jet. No vibronic structure has been observed in the excitation spectrum. The intensity of fluorescence gradually increases with the excitation energy in the 25,500-28,700 cm(-1) region, indicating that the geometry of the molecule substantially changes upon photoexcitation. The dispersed fluorescence spectrum is anomaly Stokes-shifted with respect to the excitation energy, suggesting that the S-2(1B) state is initially excited followed by rapid internal conversion from the S-2(1B) to S-1(2A) state. The fluorescence is due to the S-1(2A)-S-0(1A) transition. Density functional theory calculations at the B3LYP/6-31G(**) level have been carried out to investigate stable conformations responsible for the observed spectra. (C) 2002 Elsevier Science B.V. All rights reserved.