標題: Rotationally resolved ultrahigh-resolution laser spectroscopy of the S(2) (1)A(1)<- S(0) (1)A(1) transition of azulene
作者: Semba, Yosuke
Yoshida, Kazuto
Kasahara, Shunji
Ni, Chi-Kung
Hsu, Yen-Chu
Lin, Sheng Hsien
Ohshima, Yasuhiro
Baba, Masaaki
應用化學系
Department of Applied Chemistry
公開日期: 14-Jul-2009
摘要: We have observed rotationally resolved ultrahigh-resolution fluorescence excitation spectra of the 0(0)(0) (a-type) and 0(0)(0)+467 cm(-1) (b-type) bands of the S(2) (1)A(1)<- S(0) (1)A(1) transition of jet-cooled azulene. The observed linewidth is 0.0017 cm(-1), which corresponds to the lifetime of 3.1 ns in the S(2) state. Zeeman splitting of rotational lines is very small so that intersystem crossing to the triplet state is considered to be very slow. Inertial defect is very small and the molecule is considered to be planar in the S(0) and S(2) states (C(2 upsilon) symmetry). Rotational constants of the S(2) state are almost identical to those of the S(0) state, indicating that geometrical structure is similar in both electronic states. In this case, internal conversion (IC) by vibronic coupling is thought to be inactive. Therefore, the main radiationless transition process in the S(2) (1)A(1) state of azulene was identified to be IC to the S(1) (1)B(2) state. However, this S(2)-> S(1) IC is still slower than that of conventional polycyclic aromatic hydrocarbons. We consider it to be due to the shallower potential energy curve in the S(1) (1)B(2) state, which is also responsible for the extraordinarily fast S(1)-> S(0) IC in the isolated azulene molecule. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3168394]
URI: http://dx.doi.org/10.1063/1.3168394
http://hdl.handle.net/11536/6966
ISSN: 0021-9606
DOI: 10.1063/1.3168394
期刊: JOURNAL OF CHEMICAL PHYSICS
Volume: 131
Issue: 2
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