title: Tunneling chemical exchange reaction D + HD → D2+ H in solid HD and D2at temperatures below 1 K.
abstract: We report on a study of the exchange tunneling reaction D + HD → D2+ H in a pure solid HD matrix and in a D2matrix with a 0.23% HD admixture at temperatures between 130 mK and 1.5 K. We found that the exchange reaction rates, kexHD∼ 3 × 10-27cm3s-1in the pure HD matrix, and kexD2= 9(4) × 10-28cm3s-1in the D2matrix, are nearly independent of temperature within this range. This confirms the quantum tunnelling nature of these reactions, and their ability to proceed at temperatures down to absolute zero. Based on these observations we concluded that exchange tunneling reaction H + H2→ H2+ H should also proceed in a H2matrix at the lowest temperatures. On the other hand, the recombination of H atoms in solid H2and D atoms in solid D2is substantially suppressed at the lowest temperatures as a result of a decreased probability of resonant tunneling of atoms when they approach each other.
authors.affiliation: Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland. seshel@utu.fi.
authors.forename: S
authors.initials: S
authors.lastname: Sheludiakov
authors.affiliation: Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland. seshel@utu.fi.
authors.forename: J
authors.identifier: http://orcid.org/0000-0001-5857-1541
authors.initials: J
authors.lastname: Ahokas
authors.affiliation: Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland. seshel@utu.fi.
authors.forename: J
authors.initials: J
authors.lastname: Järvinen
authors.affiliation: Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland. seshel@utu.fi and Institute of Physics, Kazan Federal University, 18 Kremlyovskaya St., Kazan 42008, Republic of Tatarstan, Russian Federation.
authors.forename: D
authors.initials: D
authors.lastname: Zvezdov
authors.affiliation: Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland. seshel@utu.fi.
authors.forename: L
authors.initials: L
authors.lastname: Lehtonen
authors.affiliation: Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland. seshel@utu.fi.
authors.forename: O
authors.identifier: http://orcid.org/0000-0001-6045-2963
authors.initials: O
authors.lastname: Vainio
authors.affiliation: Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland. seshel@utu.fi.
authors.forename: S
authors.initials: S
authors.lastname: Vasiliev
authors.affiliation: Institute for Quantum Science and Engineering, Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA.
authors.forename: D M
authors.initials: DM
authors.lastname: Lee
authors.affiliation: Institute for Quantum Science and Engineering, Department of Physics and Astronomy, Texas A&M University, College Station, TX 77843, USA.
authors.forename: V V
authors.identifier: http://orcid.org/0000-0002-3362-3891
authors.initials: VV
authors.lastname: Khmelenko