Abstract The transformations of isolated toluene molecules under X-ray radiolysis in solid noble gas matrices at 6 K were characterized by FTIR spectroscopy. It was found that the efficiency of the radiation-induced decomposition of toluene was generally comparable to that of benzene. Meanwhile, a remarkable matrix effect was observed: toluene is more stable than benzene in an argon matrix, whereas it becomes more sensitive in the case of xenon matrix. This result was ascribed to the increasing role of upper triplet excited states in a xenon matrix. In all the matrices two main radiolysis products observed at moderate absorbed doses were benzyl radical and 5-methylene-1,3-cyclohexadiene (MCHD). Benzyl radical predominates in all the cases, while the relative contribution of MCHD strongly decreases in the row Ar-Kr-Xe. On the basis of this comparison, the formation of MCHD was tentatively attributed to the rearrangement of excited primary toluene radical cations. Possible scheme of the radiation-induced processes is discussed.

中文翻译：

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低温基质中孤立甲苯分子的辐射诱导转化：更好地理解凝聚相中的分子辐射化学

摘要 利用FTIR 光谱表征了6 K 固体惰性气体基质中X 射线辐解作用下分离出的甲苯分子的转化。发现甲苯的辐射诱导分解效率通常与苯相当。同时，观察到显着的基质效应：甲苯在氩基质中比苯更稳定，而在氙基质的情况下变得更敏感。这一结果归因于氙气矩阵中上部三重激发态的作用越来越大。在所有基质中，在中等吸收剂量下观察到的两种主要辐射分解产物是苄基自由基和 5-亚甲基-1,3-环己二烯 (MCHD)。在所有情况下，苄基自由基占主导地位，而 MCHD 的相对贡献在 Ar-Kr-Xe 行中显着降低。在此比较的基础上，MCHD 的形成暂时归因于激发的初级甲苯自由基阳离子的重排。讨论了辐射诱导过程的可能方案。