Tunneling chemical reactions in solid parahydrogen: direct measurement of the rate constants of R + H2 --> RH + H (R = CD3,CD2H,CDH2,CH3) at 5 K.
Tunneling chemical reactions in solid parahydrogen: direct measurement of the rate constants of R + H2 --> RH + H (R = CD3,CD2H,CDH2,CH3) at 5 K.
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DOI：
10.1063/1.1642582
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发表时间：
2004-02
期刊：
影响因子：
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通讯作者：
H. Hoshina;M. Fushitani;T. Momose;T. Shida
中科院分区：
文献类型：
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作者：
H. Hoshina;M. Fushitani;T. Momose;T. Shida
本文用傅里叶变换红外光谱研究了仲氢晶体中氘代甲基自由基与氢分子之间的化学反应。根据5 K下固体仲氢中反应物和产物的振转吸收带强度随时间的变化，直接确定了反应R + H ~ 2 → RH + H（R = CD_3，CD_2 H，CD_H ~ 2）在振动基态的隧穿速率.每个反应的隧穿速率被发现不同的明确取决于在甲基自由基的氘代程度。CD 3、CD 2 H和CDH 2系统的隧穿速率分别为3.3 × 10（-6）s（-1）、2.0 × 10（-6）s（-1）和1.0 × 10（-6）s（-1）。相反，CH 3自由基和氢分子之间的隧穿反应在一周的时间内没有进行。CH 3自由基反应的隧穿速率的上限估计为8 × 10（-8）s（-1）。
Tunneling chemical reactions between deuterated methyl radicals and the hydrogen molecule in a parahydrogen crystal have been studied by Fourier transform infrared spectroscopy. The tunneling rates of the reactions R + H2 --> RH + H (R = CD3,CD2H,CDH2) in the vibrational ground state were determined directly from the temporal change in the intensity of the rovibrational absorption bands of the reactants and products in each reaction in solid parahydrogen observed at 5 K. The tunneling rate of each reaction was found to differ definitely depending upon the degree of deuteration in the methyl radicals. The tunneling rates were determined to be 3.3 x 10(-6) s(-1), 2.0 x 10(-6) s(-1), and 1.0 x 10(-6) s(-1) for the systems of CD3, CD2H, and CDH2, respectively. Conversely, the tunneling reaction between a CH3 radical and the hydrogen molecule did not proceed within a week's time. The upper limit of the tunneling rate of the reaction of the CH3 radical was estimated to be 8 x 10(-8) s(-1).