Journal of Physical Chemistry A, Vol.101, No.13, 2423-2428, 1997
Laser-Induced Fluorescence Spectroscopy of Jet-Cooled Benzophenone Ketyl Radical
The D-1 <-- D-0 transition of jet-cooled benzophenone ketyl radical (BPK) and its deuteride was studied by using laser-induced fluorescence (LIF) spectroscopy. BPK was generated by the 248 nm photolysis of alpha-phenylbenzoin, and its vibrationally resolved LIF excitation and emission spectra were obtained for the first time. The 18 451 cm(-1) band was assigned to the 0(0)(0) band of the D-1 <-- D-0 transition of BPK. Two vibrational modes of BPK with 65 and 84 cm(-1) in the first excited state were assigned to the in-phase and out-of-phase torsional motions of the phenyl rings, respectively. The vibrational mode with 980 cm(-1) was tentatively assigned to the C-O stretching mode. The mode of 74 cm(-1) in the ground state was assigned to the in-phase torsional mode. It was confirmed that the torsional motions do not couple with the C-O stretching and O-H rotational motions. The force field analysis and the simple Franck-Condon calculation were made. The measured fluorescence lifetimes of BPK and its deuteride are short and consistent with those in the gas and liquid phases at room temperature.
Keywords:DIPHENYLKETYL RADICALS;ABSORPTION-SPECTRA;FLASH-PHOTOLYSIS;EXCITATION;STATE;DYNAMICS;PHOTOCHEMISTRY;BENZALDEHYDE;COMBINATION