Ultrahigh-resolution laser spectroscopy of the S-1 B-1(2u) <- S-0 (1)A(g) transition of perylene

作者：Kowaka Yasuyuki; Suganuma Yoshitake; Ashizawa Noritaka; Nakayama Naofumi; Goto Hitoshi; Ishimoto Takayoshi; Nagashima Umpei; Baba Masaaki^*

来源：Journal of Molecular Spectroscopy, 2010, 260(1): 72-76.

DOI：10.1016/j.jms.2009.11.011

• Perylene
• Rotationally resolved fluorescence
• excitation spectrum
• Rotational constants
• Radiationless transition
• Ab initio theoretical calculation

A rotationally resolved ultrahigh-resolution fluorescence excitation spectrum of the S-1 <- S-0 transition of perylene has been observed using a collimated supersonic jet technique in conjunction with a single-mode UV laser. We assigned 1568 rotational lines of the 0(0)(0) band, and accurately determined the rotational constants. The obtained value of inertial defect was positive, accordingly, the perylene molecule is considered to be planar with D-2h symmetry. We determined the geometrical structure in the S-0 state by ab initio theoretical calculation at the RHF/6-311+G(d,p) level, which yielded rotational constant values approximately identical to those obtained experimentally. Zeeman broadening of each rotational line with the external magnetic field was negligibly small, and the mixing with the triplet state was shown to be very small. This evidence indicates that intersystem crossing (ISC) in the S-1 B-1(2u) state is very slow. The rate of internal conversion (IC) is also inferred to be small because the fluorescence quantum yield is high. The rotational constants of the S-1 B-1(2u) state were very similar to those of the S-0 (1)A(g) state. The slow internal conversion (IC) at the S-1 zero-vibrational level is attributed to a small structural change upon electronic transition.

• 出版日期2010-3