The Overhauser effect for atomic hydrogen in a solid H2-matrix

Katunin, Andrzej; Lukashevich, I. I.; Orosmamatov, S.T.; Sklyarevskii, V.V.; Suraev, V. V.; Филиппов, В. В.; Fivippov, N.I.; Shevtsov, V. A.

doi:10.1016/0375-9601(82)90765-4

Cited by 6 publications

(2 citation statements)

References 3 publications

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“…The electron spin-lattice relaxation times were measured previously in several experiments. It turned out that the relaxation times measured at 0.3 T [14,15,16], 0.86 T [17], 4.6 T [18] and the present work agree with each other within 1-2 orders of magnitude. Based on the assumption that the electron-spin relaxation at helium temperatures and below proceeds via the direct process, a strong, 1…”

Section: Resultssupporting

confidence: 85%

Dynamic Nuclear Polarization and Relaxation of H and D Atoms in Solid Mixtures of Hydrogen Isotopes

et al. 2016

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We report on a study of Dynamic Nuclear Polarization and electron and nuclear spin relaxation of atomic hydrogen and deuterium in solid molecular matrices of H 2 , D 2 , and HD mixtures. The electron and nuclear spin relaxation times (T 1e and T 1N ) were measured within the temperature range 0.15-2.5 K in a magnetic field of 4.6 T, conditions which ensure a high polarization of electron spins. We found that T 1e is nearly temperature independent in this temperature range, while T 1N decreased by 2 orders of magnitude. Such strong temperature dependence is typical for the nuclear Orbach mechanism of relaxation via the electron spins. We found that the nuclear spins of H atoms in solid D 2 and D 2 :HD can be efficiently polarized by the Overhauser effect. Pumping the forbidden transitions of H atoms also leads to DNP, with the efficiency strongly dependent on the concentration of D atoms. This behaviour indicates the Cross effect mechanism of the DNP and nuclear relaxation, which turns out to be well resolved in the conditions of our experiments. Efficient DNP of H atoms was also observed when pumping the middle D line located in center of the ESR spectrum. This phenomenon can be explained in terms of clusters or pairs of H atoms with strong exchange interaction. These clusters have partially allowed transitions in the center of the ESR spectrum and DNP may be created via the resolved Cross effect.

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Section: Resultssupporting

confidence: 85%

Dynamic Nuclear Polarization and Relaxation of H and D Atoms in Solid Mixtures of Hydrogen Isotopes

et al. 2016

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“…Concomitantly, the area under the a-d line increased by the same amount as the area under the b-c line decreased. This effect can be caused by cross relaxation through the forbidden c-a transition (the Overhauser effect), which was observed previously for H in H 2 at T 1:3 K [19]. By measuring the destruction of the b-c line at high enough values of the ESR excitation power (so that the destruction rate no longer depends on the ESR power), we extract the relaxation time of the forbidden c-a transition T ca 5 s, i.e., about the same as T da .…”

Section: Laboratory Of Atomic and Solidmentioning

confidence: 56%

Exotic Behavior of Hydrogen Atoms in SolidH2at Temperatures below 1 K

et al. 2006

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We present the first magnetic resonance study of atomic hydrogen embedded in solid H2 films for temperatures 150-900 mK. We found that at T approximately 150 mK average concentrations of H atoms of order 10(18 cm(-3) are very stable against recombination during two weeks of observations. The distribution of the population of the two lowest hyperfine states is found to be non-Boltzmann, with a very large occupation of the ground state. We consider the possibility of formation in solid H2 of regions with high local concentrations of H atoms, where collective quantum phenomena might occur.

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