Spatial Diffusion of Hydrogen Atoms in Normal and Para-Hydrogen Molecular Films at Temperature 0.7 K
: Sheludiakov S., Wetzel C. K., Lee D. M., Khmelenko V. V., Järvinen J., Ahokas J., Vasiliev S.
Publisher: Springer Nature
: 2024
: Journal of Low Temperature Physics
: JOURNAL OF LOW TEMPERATURE PHYSICS
: J LOW TEMP PHYS
: 215
: 5-6
: 336
: 356
: 21
: 0022-2291
: 1573-7357
DOI: https://doi.org/10.1007/s10909-024-03053-w(external)
: https://link.springer.com/article/10.1007/s10909-024-03053-w(external)
: https://research.utu.fi/converis/portal/detail/Publication/387220279(external)
We report on electron spin resonance studies of H atoms stabilized in solid H2 flms at temperature 0.7 K and in a magnetic feld of 4.6 T. The H atoms were produced by bombarding H2 flms 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 flms made of para-H2 gas with a small ortho-H2 concentration (0.2% ortho-H2) as compared with those made from normal H2 gas content (75% ortho-H2). We also studied the infuence of ortho-H2 molecules on spatial difusion of H atoms in solid H2 flms. The spatial difusion of H atoms in both normal and para-H2 flms is faster than the difusion obtained from the measurement of H atom recombination. The rate of spatial difusion of H atoms in para-H2 flms was slower in comparison with that in the normal H2 flms. We discuss possible explanations of these observations.