The bromide-bromomethyl radical dimer complex: Anion photoelectron spectroscopy and CCSD(T) calculations

The gas phase anion photoelectron spectrum associated with the bromide-bromomethyl radical is presented. The stabilisation energy and electron binding energy, a property corresponding to the electron affinity of the neutral complex, are determined. Ab initio MP2 optimisations (with additional CCSD(T) energies) found two forms of the complex, a hydrogen bonded complex and a halogen bonded complex. The halogen bonded complex was found to exhibit C_2v symmetry and the hydrogen bonded complex exhibited C_s symmetry. Comparison between the experimental data and the computational data allow conclusions to be drawn about the structure of the experimentally observed species.