ИСТИНА

Fluoroform is considered as an ecologically acceptable alternative to chlorofluorocarbons (CFCs). In contrast to CFCs, this compound is stable to near UV light, but it could be decomposed by VUV or ionizing radiation. Basic mechanisms of such processes were revealed in our recent matrix isolation studies [1, 2]. An important feature of these processes is prominent environment effect on the decomposition pathways. It is known that fluoroform yields weak intermolecular complexes with different molecules, including those of interest for atmospheric chemistry. These species are stable, at least, under matrix isolation conditions. The impact of intermolecular interactions on the processes induced by high-energy radiation is poorly studied, and this is an important issue for atmospheric chemistry, astrochemistry and basic chemical physics. In this work we report a FTIR matrix isolation study on the radiolysis at 5 K and post- irradiation thermal reactions occurring in the CHF3/X/Ng systems (X = CO, H2O and N2O, Ng = Noble gas). It was shown, that codeposition of CHF3/X/Ng gas mixtures led to formation of CHF3...X complexes [3, 4]. The spectroscopic characteristics of complexes calculated at the CCSD(T) and MP2 levels of theory good agreement with experimental observations. In the case of CO complexes, the effect of complexation on the efficiency of radiation- induced decomposition of CHF3 is relatively small and radiolysis results in stabilization of the CF3...CO complexes. On the other hand, in the case of CHF3/N2O/Ng systems, the complexation leads to significant increase of the rate of radiation-induced degradation of fluoroform. Furthemore, we have observed direct formation of CF2O and CF2O…HF as major radiolysis products. The amount of CF2O…HF complexes increases upon annealing the irradiated samples to 15 – 30 K , which may indicate involvement of thermal reactions of radiolytically produced oxygen atoms with fluoroform at low temperatures. The mechanisms of radiation-induced transformations of different complexes and spectroscopic features of their products are discussed. . References 1 I. S. Sosulin, E. S. Shiryaeva, V. I. Feldman, Radiat. Phys. Chem., 2017, 138, 60-66. 2 I. S. Sosulin, E. S. Shiryaeva, D.A. Tyurin, V. I. Feldman, J. Chem. Phys., 2017, 147, 131102 3 I. S. Sosulin, E. S. Shiryaeva, D. A. Tyurin, V. I. Feldman. J. Phys. Chem. A, 122(16):4042–4047, 2018 4 I. S. Sosulin, D. A. Tyurin, , V. I. Feldman. Struct. Chem., accepted, 2018