Decay of hydrogen(deuterium) atoms in solid hydrogen at 4.2 K: rate constant for tunneling reaction hydrogen (deuterium, hydrogen deuteride) + hydrogen (deuterium) atom

Miyazaki, Tsuyoshi; Iwata, Nobuchika; Lee, Kwang Pill; Fueki, Kenji

doi:10.1021/j100345a092

Cited by 44 publications

(19 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1 H+H 2 → H 2 + H and its isotope substitutes are the simplest and most essential of a lot of tunneling reactions reported so far. [2][3][4] Miyazaki et al 5 found using electron-spin-resonance ͑ESR͒ spectroscopy that one D atom produced by the ␥ radiolysis of solid HD reacts with one of its nearest-neighboring HD molecules,…”

Section: Introductionmentioning

confidence: 99%

Tunneling chemical reactions D+H2→DH+H and D+DH→D2+H in solid D2–H2 and HD–H2 mixtures: An electron-spin-resonance study

Kumada

2006

The Journal of Chemical Physics

View full text Add to dashboard Cite

Tunneling chemical reactions D + H2 --> DH + H and D + DH --> D2 + H in solid HD-H2 and D2-H2 mixtures were studied in the temperature range between 4 and 8 K. These reactions were initiated by UV photolysis of DI molecules doped in these solids for 30 s and followed by measuring the time course of electron-spin-resonance (ESR) intensities of D and H atoms. ESR intensity of D atoms produced by the photolysis decreases but that of H atoms increases with time. Time course of the D and H intensities has the fast and slow processes. The fast process, which finishes within approximately 300 s after the photolysis, is assigned to the reaction of D atom with one of its nearest-neighboring H2 molecules, D(H2)n(HD)(12-n) --> H(H2)(n-1)(HD)(13-n) or D(H2)n(D2)(12-n) --> H(HD)(H2)(n-1)(D2)(12-n) for 12 > or = n > or = 1. Rate constant for the D + H2 reaction between neighboring D atom-H2 molecule pair is determined to be (7.5 +/- 0.7) x 10(-3) s(-1) in solid HD-H2 and (1.3+/-0.3) x 10(-2) s(-1) in D2-H2 at 4.1 K, which is very close to that calculated based on the theory of chemical reaction in gas phase by Hancock et al. [J. Chem. Phys. 91, 3492 (1989)] and Takayanagi and Sato [J. Chem. Phys. 92, 2862 (1990)]. This rate constant was found to be independent of temperature up to 7 K within experimental error of +/-30%. The slow process is assigned to the reaction of D atom produced in a cage fully surrounded by HD or D2 molecules, D(HD)12 or D(D2)12. This D atom undergoes the D + DH reaction with one of its nearest-neighboring HD molecules in solid HD-H2 or diffuses to the neighbor of H2 molecules to allow the D + H2 reaction in solid HD-H2 and D2-H2. The former is the main channel in solid HD-H2 below 6 K where D atoms diffuse very slowly, whereas the latter dominates over the former above 6 K. Rate for the reactions in the slow process is independent of temperature below 6 K but increases with the increase in temperature above 6 K. We found that the increase is due to the increase in hopping rate of D atoms to the neighbor of H2 molecules. Rate constant for the D + DH reaction was found to be independent of temperature up to 7 K as well.

show abstract

Section: Introductionmentioning

confidence: 99%

Tunneling chemical reactions D+H2→DH+H and D+DH→D2+H in solid D2–H2 and HD–H2 mixtures: An electron-spin-resonance study

Kumada

2006

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…The tunneling abstraction reactions by H and D in hydrogen molecules (H 2 , HD, D 2 , and their mixtures) have been investigated experimentally − in the solid state at very low temperature. However, no report has been published on the reaction in liquid helium.…”

Section: Introductionmentioning

confidence: 99%

Tunneling Abstraction Reactions of Tritium Atoms with HD and with Mixtures of H₂ and D₂ in Superfluid and Normal-Fluid ³He−⁴He Media at 1.3 K

et al. 1998

Self Cite

View full text Add to dashboard Cite

The abstraction reactions, T + HD(DH) f HT(DT) + D(H) and T + H 2 (D 2 ) f HT(DT) + H(D) were studied experimentally in liquid 3 He-4 He media at 1.3 K and theoretically using the gas-phase reaction model. The experimental reaction system has two characteristics; one is that the tritium atom (T) is produced from one of the constituents, 3 He, through 3 He(n, p)T nuclear reaction, and the other is that superfluid or normalfluid reaction medium can be chosen arbitrarily by changing the composition and temperature of the sample. The experimental isotope effect defined by {[HT]/[H 2 ]}/{[DT]/[D 2 ]} for the reactions T + H 2 (D 2 ) f HT-(DT) + H(D) was found to be 158 in superfluid and 146 in normal-fluid solutions. The large isotope effects observed were qualitatively explained via quantum mechanical tunneling on the basis of the theoretical calculations of thermal rate constants for these reactions. In the T + HD(DH) f HT(DT) + D(H) reactions, the experimental isotope effect was <19.8. From the considerations on both the reaction processes based on the experimental results and the theoretical calculations, it has been suggested that the quantum mechanical tunneling abstraction through van der Waals complex plays a predominant role for both the reactions.

show abstract

“…Unfortunately, from the earliest investigations of H atoms in solid H 2 , it became clear that some tunnelling processes and molecular recombination could lead to a decrease in the concentration of stabilized H atoms [2]. The detailed investigations of the processes of quantum diffusion and tunnelling reactions of H atoms in solid H 2 at T = 1.35-4.2 K were performed by Ivliev et al [3] and later by Miyazaki et al [4][5][6]. They established that the decay of H atoms could take place in solid H 2 by tunnelling migration, in which H atoms tunnel through a chain of H 2 molecules according to the reaction H + H 2 ® H 2 + H (1) thereby travelling through the solid H 2 to recombine with another H atom.…”

Section: Introductionmentioning

confidence: 99%

“…Gordon et al [8,12] suggested that high concentrations of H atoms could be stabilized at low temperatures by means of reactions (3) and (4). In their approach, a gas mixture of hydrogen, deuterium and helium gas was transported through a radio frequency discharge onto the surface of superfluid He contained in a small beaker, at a temperature 1.5 K. The jet of impurity and helium gases penetrates the surface of the superfluid He, and then forms a snow-like solid which settles to the bottom of the collection beaker.…”

Section: Introductionmentioning

confidence: 99%

ESR investigation of hydrogen and deuterium atoms in impurity-helium solids

Kiselev

Khmelenko

Bernard

et al. 2003

Low Temperature Physics

View full text Add to dashboard Cite

pendence of H and D atom concentrations has been investigated for Im-He samples with different initial ratios of hydrogen and deuterium ranging from 1:20 to 1:1.The satellite ESR lines associated with the dipolar coupling of electron spins of H and D atoms to the nuclear moments of the hydrogen nuclei found in neighboring molecules have been observed in Im-He solids. The forbidden hyperfine transition of atomic hydrogen involving the mutual spin flips of electrons and protons has also been observed.

show abstract

Decay of hydrogen(deuterium) atoms in solid hydrogen at 4.2 K: rate constant for tunneling reaction hydrogen (deuterium, hydrogen deuteride) + hydrogen (deuterium) atom

Cited by 44 publications

References 0 publications

Tunneling chemical reactions D+H2→DH+H and D+DH→D2+H in solid D2–H2 and HD–H2 mixtures: An electron-spin-resonance study

Tunneling chemical reactions D+H2→DH+H and D+DH→D2+H in solid D2–H2 and HD–H2 mixtures: An electron-spin-resonance study

Tunneling Abstraction Reactions of Tritium Atoms with HD and with Mixtures of H₂ and D₂ in Superfluid and Normal-Fluid ³He−⁴He Media at 1.3 K

ESR investigation of hydrogen and deuterium atoms in impurity-helium solids

Contact Info

Product

Resources

About

Decay of hydrogen(deuterium) atoms in solid hydrogen at 4.2 K: rate constant for tunneling reaction hydrogen (deuterium, hydrogen deuteride) + hydrogen (deuterium) atom

Cited by 44 publications

References 0 publications

Tunneling chemical reactions D+H2→DH+H and D+DH→D2+H in solid D2–H2 and HD–H2 mixtures: An electron-spin-resonance study

Tunneling chemical reactions D+H2→DH+H and D+DH→D2+H in solid D2–H2 and HD–H2 mixtures: An electron-spin-resonance study

Tunneling Abstraction Reactions of Tritium Atoms with HD and with Mixtures of H2 and D2 in Superfluid and Normal-Fluid 3He−4He Media at 1.3 K

ESR investigation of hydrogen and deuterium atoms in impurity-helium solids

Contact Info

Product

Resources

About

Tunneling Abstraction Reactions of Tritium Atoms with HD and with Mixtures of H₂ and D₂ in Superfluid and Normal-Fluid ³He−⁴He Media at 1.3 K