High-resolution fluorescence excitation spectra of jet-cooled benzyl and p-methylbenzyl radicals

Vibronic Emission Spectrum ofp-Xylyl Radical

“…They concluded that the à state symmetry of p-xylyl is 2 A 2 , analogous to benzyl itself. Miller and co-workers confirmed their conclusion in their high-resolution, rotationally resolved analysis (3). By comparing band contours, Cossart-Magos and Cossart (12) also assigned the 6a 1 0 and 6b 1 0 transitions.…”

“…Equation [3] implies that the symmetry of ͉T͘ cannot change in the transition. For the p-xylyl radical, if the torsional motion of the methyl group is taken into account, one should use the molecular symmetry group G 12 (14).…”

“…Figure 1 shows the molecular-fixed axis system of p-xylyl showing the moment of inertia axis in the C 2v symmetry approximation. (There is a nearby B 2 B 2 state which interacts with the à 2 A 2 state, but as this study pertains to the X state, we need not go into the details of these interactions, which have been discussed extensively before (12,3). )…”

“…The electronic structure of benzyl and the three isomeric methyl-substituted benzyl radicals (xylyls) have been the subject of much experimental and theoretical work (1)(2)(3). The effects of methyl substitution in the ortho, meta, and para positions have been studied by many different groups (4 -11).…”

Observation of Vibronic Emission Spectrum of the Jet-Cooled m-Cyanobenzyl Radical in a Corona Excitation

“…Also, the torsional contribution of the methyl rotor has been obtained from analysis of the rotational contours of the high resolution Fourier transform emission spectra. 5 As for halogen-substituted benzyl-type radicals, the vibrational modes of fluorobenzyl radicals have been determined using different spectroscopic techniques such as laser induced fluorescence (LIF) 6,7 and coronal excitation. [8][9][10] Weakly emitting chlorobenzyl radicals have been recently identified from the vibronic emission spectra, [11][12][13] in which the sequence of electronic energy of the lowest excited electronic state shows a similar tendency to the chlorotoluenes.…”