Journal of Physical Chemistry A, Vol.124, No.37, 7491-7499, 2020
VUV Photofragmentation of Chloroiodomethane: The Iso-CH2I-Cl and Iso-CH2CI-l Radical Cation Formation
Dihalomethanes XCH2Y (X and Y = F, Cl, Br, and I) are a class of compounds involved in several processes leading to the release of halogen atoms, ozone consumption, and aerosol particle formation. Neutral dihalomethanes have been largely studied, but chemical physics properties and processes involving their radical ions, like the pathways of their decomposition, have not been completely investigated. In this work the photodissociation dynamics of the ClCH2I molecule has been explored in the photon energy range 9-21 eV using both VUV rare gas discharge lamps and synchrotron radiation. The experiments show that, among the different fragment ions, CH2I+ and CH2Cl-, which correspond to the Cl- and I-losses, respectively, play a dominant role. The experimental ionization energy of CICH2I and the appearance energies of the CH2I+ and CH2Cl+ ions are in agreement with the theoretical results obtained at the MP2/CCSD(T) level of theory. Computational investigations have been also performed to study the isomerization of geminal [ClCH2I](center dot+) into the iso-chloroiodomethane isomers: CH2I-Cl](center dot+) and [CH2Cl-I](center dot+).