title: Infrared spectroscopy of chloromethyl radical in solid parahydrogen and its nuclear spin conversion.
abstract: We present high-resolution infrared absorption spectra of chloromethyl radical produced by in situ UV photolysis of chloroiodomethane isolated in solid parahydrogen. The radicals were stable over a few days in solid parahydrogen kept at 3.6 K. Analysis of the rotation-vibration spectra revealed that the radical exhibited quantized one-dimensional rotational motion about the C-Cl bond, while the ortho and para nuclear spin species were still clearly distinguishable in the spectra. Temporal change of the spectra indicated that the nuclear spin conversion between the ortho and para nuclear spin species of the radical in solid parahydrogen occurred in a time scale of a few hours at 3.6 K. It was also found that the nuclear spin conversion became significantly slower in a higher concentration of chloroiodomethane.
authors.affiliation: Department of Chemistry, and ‡Department of Physics and Astronomy, The University of British Columbia , 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Miyamoto
authors.forename: Masaaki
authors.initials: M
authors.lastname: Tsubouchi
authors.forename: Takamasa
authors.initials: T
authors.lastname: Momose