ESR study of atomic hydrogen and tritium in solid T$_{2}$ and T$_{2}$:H$_{2}$ matrices below 1K

S. Sheludiakov; J. Ahokas; J. Järvinen; O. Vainio; L. Lehtonen; D. Zvezdov; S. Vasiliev; D. M. Lee; V. V. Khmelenko

doi:10.1039/C6CP06933A

paper

ESR study of atomic hydrogen and tritium in solid T $_{2}$ and T $_{2}$ :H $_{2}$ matrices below 1K

arXiv:1609.06564 · doi:10.1039/C6CP06933A

Abstract

We report on the first ESR study of atomic hydrogen and tritium stabilized in a solid T $_{2}$ and T $_{2}$ :H $_{2}$ matrices down to 70mK. The concentrations of T atoms in pure T $_{2}$ approached $2 \times 1 0^{20}$ cm $^{- 3}$ and record-high concentrations of H atoms $\sim 1 \times 1 0^{20}$ cm $^{- 3}$ were reached in T $_{2}$ :H $_{2}$ solid mixtures where a fraction of T atoms became converted into H due to the isotopic exchange reaction T+H $_{2} \to$ TH+H. The maximum concentrations of unpaired T and H atoms was limited by their recombination which becomes enforced by efficient atomic diffusion due to a presence of a large number of vacancies and phonons generated in the matrices by $β$ -particles. Recombination also appeared in an explosive manner both being stimulated and spontaneously in thick films where sample cooling was insufficient. We suggest that the main mechanism for H and T migration is physical diffusion related to tunneling or hopping to vacant sites in contrast to isotopic chemical reactions which govern diffusion of H and D atoms created in H $_{2}$ and D $_{2}$ matrices by other methods.

ESR study of atomic hydrogen and tritium in solid T2​ and T2​:H2​ matrices below 1K

Abstract

ESR study of atomic hydrogen and tritium in solid T $_{2}$ and T $_{2}$ :H $_{2}$ matrices below 1K