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.