Spatial Diffusion of Hydrogen Atoms in Normal and Para-Hydrogen Molecular Films at Temperature 0.7 K

期刊论文
发表日期：

2024年2月27日

查看全文

S. Sheludiakov,
C. K. Wetzel,
D. M. Lee,
V. V. Khmelenko,
J. Järvinen,
J. Ahokas,
S. Vasiliev

摘要

We report on electron spin resonance studies of H atoms stabilized in solid H $_{2}$ $_{2}$ films at temperature 0.7 K and in a magnetic field of 4.6 T. The H atoms were produced by bombarding H $_{2}$ $_{2}$ films with 100 eV electrons from a radiofrequency discharge run in the sample cell. We observed a one order of magnitude faster H atom accumulation in the films made of para-H $_{2}$ $_{2}$ gas with a small ortho-H $_{2}$ $_{2}$ concentration (0.2% ortho-H $_{2}$ $_{2}$ ) as compared with those made from normal H $_{2}$ $_{2}$ gas content (75% ortho-H $_{2}$ $_{2}$ ). We also studied the influence of ortho-H $_{2}$ $_{2}$ molecules on spatial diffusion of H atoms in solid H $_{2}$ $_{2}$ films. The spatial diffusion of H atoms in both normal and para-H $_{2}$ $_{2}$ films is faster than the diffusion obtained from the measurement of H atom recombination. The rate of spatial diffusion of H atoms in para-H $_{2}$ $_{2}$ films was slower in comparison with that in the normal H $_{2}$ $_{2}$ films. We discuss possible explanations of these observations.