Transient resonance Raman and density functional theory investigation of bromomethyl radical

We have obtained transient resonance Raman spectra of CH2Br produced following A-band excitation of dibromomethane and performed density functional theory computations to estimate the vibrational frequencies and electronic transition energies of the CH2Br radical. Our results indicate the CH2Br radical has a C-Br bond longer than in the parent CH2Br2 molecule but shorter than in a typical bromoalkane. Both the experimental and calculated resonance Raman spectra which display a strong overtone progression in the nominal C-Br stretch mode suggest that the first excited electronic state of the CH2Br radical experiences motion mostly along the C-Br bond in the Franck-Condon region. (C) 2000 Published by Elsevier Science B.V.