Studies of nuclear polarization of hydrogen atoms embedded in solid molecular hydrogen and hydrogen deuteride films

Abstract

We report on an electron-spin resonance study of nuclear polarization of hydrogen atoms embedded in solid H-2 and HD films at temperatures 0.1-1.5 K and in a high magnetic field of 4.6 T. Similar to our previous work [Phys. Rev. Lett. 122, 225301 (2019)], we observed a build-up of the spontaneously (p similar or equal to 0.35) and highly (p similar or equal to 0.75) nuclear polarized phases of H atoms in the as-deposited H-2 films. However, we did not obtain an enhanced nuclear polarization of H atoms in the regions of their small local concentration. We also failed to observe enhanced nuclear polarization for H atoms in the annealed H-2 films as well as in the as-deposited HD sample. These observations tend to support our previous explanation for the build-up of high nuclear polarization due to the formation of weakly-bound triplet H-2 molecules. Published under license by AIP Publishing.