The radiation-induced chemistry in solid xenon matrices

Abstract

The paper presents an overview of recent studies on the radiation-chemical transformations of guest molecules in solid xenon induced by fast electrons and x-ray irradiation. Specific features of the experimental approach based on combination of matrix isolation IR and EPR spectroscopy are briefly outlined (with particular impact on using monoisotopic and isotopically enriched xenon matrices). The results reveal rich and diverse radiation-induced chemistry in solid xenon, which is considered in the following major aspects: (1) matrix-induced and matrix assisted transformations of the primary guest radical cations; (2) production and dynamics of hydrogen atoms; (3) formation of xenon hydrides. Finally, preliminary results on the radiation-induced generation of oxygen atoms and ions in solid xenon are presented.

Matrix-Isolation Studies on the Radiation-Induced Chemistry in H2O/CO2 Systems: Reactions of Oxygen Atoms and Formation of HOCO Radical

“…Detailed explanation of possible mechanisms can be found elsewhere. 22,61 Unlike photolysis, the radiolysis may lead to population of different excited states; therefore, the whole picture may be more complicated. As was shown previously, 61 the energy transfer is rather effective and it results in dissociation of isolated molecules with high yield.…”

“…An isolated molecule is affected mainly in indirect ways, that is, because of charge and excitation transfer. Detailed explanation of possible mechanisms can be found elsewhere. , Unlike photolysis, the radiolysis may lead to population of different excited states; therefore, the whole picture may be more complicated. As was shown previously, the energy transfer is rather effective and it results in dissociation of isolated molecules with high yield.…”

“…Basic features of our experimental approach for matrix isolation studies of the radiation-induced processes were described previously. , All the experiments were carried out using an original closed-cycle helium cryostat designed in our laboratory on the basis of a SHI RDK-101E cryocooler. Mixtures of H 2 O, CO 2 , and noble gases (Ar, Kr, or Xe) in typical dilution 1:1:(1000–1500) were prepared in glass vacuum line following standard manometric techniques.…”

Radiation-induced transformations of matrix-isolated formic acid: evidence for the HCOOH → HOCO + H channel

“…Our experimental approach of radiation-chemical experiments in solid noble gas (Ng) matrices doped with guest molecules has been generally described elsewhere. 34,[40][41][42][43][44] Formic acid vapours were mixed with an excess amount of an appropriate noble gas in a glass vacuum line following a standard manometric technique. Xe (99.9996%), Kr (99.99%), Ar (99.998%) and Ne (99.996%) were used as received for the preparation of the mixtures with the typical HCOOH to Ng ratio of 1 : 1000 (the ratio of 1 : 2500 was used in the case of a HCOOH/Ne sample).…”

Matrix site effects on vibrational frequencies of HXeCCH, HXeBr, and HXeI: a hybrid quantum-classical simulation

“…The UV photolysis of the HY precursors in the noble-gas matrix produces these HNgY compounds, and a unique electronic character and also the formation process of the HNgY compounds has been the focus of intensive research. The preparation of the noble-gas compounds in large Xe clusters by UV photolysis [8][9][10][11] and also by fast electrons and X-ray irradiation in the Xe matrix 12,13 have been reported in the literature as well.…”