Mechanism of the radiation-induced transformations of fluoroform in solid noble gas matrixes

Abstract The X-ray induced transformations in the CHF 3 /Ng systems (Ng=Ne, Ar, Kr or Xe) at 6 K were studied by FTIR spectroscopy. The radiation-induced decomposition of CHF 3 was found to be rather inefficient in solid xenon with low ionization energy, which suggests primary significance of the positive hole transfer from matrix to the fluoroform molecule. CF 3 • , : C F 2 , CHF 2 • and CF 4 were identified as the products of low-temperature radiolysis in all the noble gas matrixes. In addition, the anionic complex HF ⋯ CF 2 − was detected in Ne and Ar matrixes. The radiolysis also resulted in formation of noble gas compounds (HArF in argon, HKrF in krypton, and XeF 2 in xenon). While XeF 2 and HArF were essentially formed directly after irradiation (presumably due to reactions of ’hot’ fluorine atoms), HKrF mainly resulted from annealing of irradiated samples below 20 K due to thermally induced mobility of trapped fluorine atoms. In both krypton and xenon matrixes, the thermally induced reactions of F atoms occur at lower temperatures than those of H atoms, while the opposite situation is observed in argon. The mechanisms of the radiation-induced processes and their implications are discussed.