Tanskanen Hanna, Khriachtchev Leonid, Lundell Jan, Räsänen Markku
Department of Chemistry, University of Helsinki, P.O. Box 55, FIN-00014 Helsinki, Finland.
J Chem Phys. 2004 Nov 1;121(17):8291-8. doi: 10.1063/1.1799611.
We investigate the formation mechanism of HXeCCXeH in a Xe matrix. Our experimental results show that the HXeCCXeH molecules are formed in the secondary reactions involving HXeCC radicals. The experimental data on the formation of HXeCCXeH is fully explained based on the model involving the HXeCC+Xe+H-->HXeCCXeH reaction. This reaction is the first case when a noble-gas hydride molecule is formed from another noble-gas molecule. In addition, we investigate the (12)C/(13)C isotope effect on the vibrational properties of organo-noble-gas hydrides (HKrCCH, HXeCCH, HXeCC, and HXeCCXeH) in noble-gas matrixes. The present experimental results and ab initio calculations on carbon isotope shifts of the vibrational modes support the previous assignments of these molecules. Upon (12)C to (13)C isotope substitution, we observed a pronounced effect on the H-Kr stretching mode of HKrCCH (downshift of 1.0-3.6 cm(-1), depending on the matrix site) and a small anomalous shift (+0.1 cm(-1)) of the H-Xe stretching mode of HXeCCH and HXeCCXeH.
我们研究了氙基质中HXeCCXeH的形成机制。我们的实验结果表明，HXeCCXeH分子是在涉及HXeCC自由基的二级反应中形成的。基于包含HXeCC + Xe + H→HXeCCXeH反应的模型，充分解释了关于HXeCCXeH形成的实验数据。该反应是首次由另一种稀有气体分子形成稀有气体氢化物分子的情况。此外，我们研究了（12）C/（13）C同位素对稀有气体基质中有机稀有气体氢化物（HKrCCH、HXeCCH、HXeCC和HXeCCXeH）振动性质的影响。目前关于振动模式碳同位素位移的实验结果和从头算计算支持了这些分子先前的归属。在（12）C到（13）C同位素取代后，我们观察到HKrCCH的H-Kr伸缩模式有明显影响（下移1.0 - 3.6 cm(-1)，取决于基质位点），以及HXeCCH和HXeCCXeH的H-Xe伸缩模式有小的反常位移（+0.1 cm(-1)）。
