Absence of recombination of neighboring H atoms in highly purified solid parahydrogen: Electron spin resonance, electron-nuclear double resonance, and electron spin echo studies
Absence of recombination of neighboring H atoms in highly purified solid parahydrogen: Electron spin resonance, electron-nuclear double resonance, and electron spin echo studies
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高纯度固体仲氢中相邻氢原子不存在重组：电子自旋共振、电子核双共振和电子自旋回波研究
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发表时间：
2002
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通讯作者：
T. Miyazaki
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作者：
T. Kumada;M. Sakakibara;T. Nagasaka;H. Fukuta;J. Kumagai;T. Miyazaki
采用电子自旋共振(ESR)、电子核双共振(ENDOR)和电子自旋回波(ESE)方法在4 K左右研究了相对浓度Xo=0.001→0.75的含邻H2分子的固体氢中H原子的扩散和复合。当假设复合的速率决定步骤是H原子的扩散时，Xo⩾0.1处的复合速率常数与估计的扩散系数一致。通过 ENDOR 谱和纵向自旋弛豫行为的分析。然而，Xo<0.1 时的复合速率常数太慢，无法使用纵向自旋弛豫和禁止自旋翻转卫星跃迁研究估计的扩散系数来解释。这一结果表明，即使一个 H 原子在其紧邻的位置找到另一个 H 原子，这些 H 原子在 Xo<0.1 时也不会反应形成 H2 分子。 H原子没有重组是由于缺乏重组所需的能量分散路径...
Diffusion and recombination of H atoms were studied in solid hydrogen containing ortho-H2 molecules at relative concentration Xo=0.001→0.75 using electron spin resonance (ESR), electron-nuclear double resonance (ENDOR), and electron spin echo (ESE) methods at around 4 K. When the rate-determining step for recombination is assumed to be the diffusion of H atoms, the rate constant for recombination at Xo⩾0.1 is consistent with the diffusion coefficient estimated from the analysis of ENDOR spectra and longitudinal spin relaxation behaviors. The recombination rate constant at Xo<0.1, however, is too slow to be explained using the diffusion coefficient estimated from longitudinal spin relaxation and forbidden spin-flip satellite transition studies. This result suggests that, even if one H atom finds another H in its immediate neighborhood, these H atoms do not react to form a H2 molecule at Xo≪0.1. The absence of recombination of H atoms is due to lack of the energy dispersion path required for the recombinati...