Electronic absorption spectrum of phenyl radical

The electronic absorption spectrum of matrix-isolated phenyl radical has been determined in the entire 52000-4000 cm(-1) region. It consists of three band systems corresponding to transitions to three excited electronic states: B-2(1), with origin at 510.5 nm/2.43 eV (epsilon = 2.8 L mol(-1) cm(-1)); (2)A(1), with lambda(max) = 235.1 nm/5.27 eV (epsilon = 220 L mol(-1) cm(-1)), and B-2(2) with the origin at 211.5 nm/5.86 eV (epsilon = 1650 L mol(-1) cm(-1)). These transitions are attributed to the phenyl radical on the basis of the strict correlation of their intensity evolution in simultaneously measured IR and UV-visible spectra. Consistent results were obtained from several independent precursors. The transition symmetries were derived from polarization measurements on photo-oriented samples. (C) 1999 Elsevier Science B.V. All rights reserved.