Raman spectrum of the phenyl radical

The Raman spectrum of phenyl radical (C6H5) isolated in low-temperature arg on matrices has been obtained. The assignments of experimentally observed f requencies are based on comparison with results of quantum chemical calcula tions (B3LYP/cc-pVTZ) and with infrared absorption bands measured for (C6H5 )-C-12 and (C6H5)-C-13 species. Analysis of the IR and Raman spectra, inclu ding IR linear dichroism, and of the isotopic shifts caused by C-12 --> C-1 3 substitution allows to reconfirm most of the previous assignments and to introduce some corrections. The prominent ring breathing mode, characterist ic for benzenoid compounds (991 cm(-1) in benzene), occurs in phenyl radica l at 998 cm(-1).