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High-resolution spectroscopy of weak and short-lived bands of the S1 B13u←S A1g transition of naphthalene

2009; American Institute of Physics; Volume: 130; Issue: 19 Linguagem: Inglês

10.1063/1.3122039

1520-9032

Kazuto Yoshida, Yosuke Semba, S. Kasahara, Takaya Yamanaka, Masaaki Baba,

Inorganic Fluorides and Related Compounds

Rotationally resolved high-resolution spectra and fluorescence decay curves have been observed for weak and short-lived vibronic bands of the S1 B13u←S0 A1g transition of naphthalene. Fluorescence lifetime of the vibronic band with an excess energy of 1390 cm−1 (000+1390 cm−1 band) is remarkably shorter than that of other bands. Zeeman splitting of rotational lines is very small, so that the main radiationless process is not intersystem crossing to the triplet state but internal conversion to the ground state. The lifetime is thought to be governed by the strength of vibronic coupling between vibrational levels of the S0 and S1 states. As for the 000+2570 cm−1 band, energy shifts were found in only a few rotational levels although the excess energy was higher than the threshold of intramolecular vibrational redistribution. We conclude that all of the rotational levels are mixed with other vibrational levels. The 000+3068 cm−1 band spectrum is fairly complicated with numerous rotational lines, which is attributed to strong vibronic coupling with the S2 B12u state.