Abstract
Ortho-para conversion in solid hydrogen with small amounts of molecular oxygen as impurity (0.01–0.5%) was studied by NMR in the temperature range 4.2–7 K. The observed conversion rate was substantially greater than that of the natural conversion process in pure solid H2 and revealed a strong dependence on temperature and the oxygen content in the sample. Obviously, the conversion is catalyzed by the large paramagnetic moments of O2 impurities. Since the influence of O2 is of very short range, the overall rate of the catalyzed conversion in the sample is determined by the relative diffusion of ortho-H2 and the O2 impurities. The diffusion coefficient was found to obey an Arrhenius behavior D(T)=3(2). 10−11.exp[96(8)/T] cm2s−1. This temperature dependence is interpreted in terms of vacancy-particle exchange by quantum tunneling through the intervening barrier.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
I. F. Silvera,Rev. Mod. Phys. 52, 393 (1980).
V. Shevtsov, A. Frolov, I. Lukashevich, E. Ylinen, P. Malmi, and M. Punkkinen,J. Low Temp. Phys. 95, 815 (1994).
A. S. Iskovskikh, A. Ya. Katunin, I. I. Lukashevich, V. V. Sklyarevskii, V. V. Suraev, V. V. Filippov, and V. A. Shevtsov,JETP Lett. 42, 30 (1985).
R. A. Zhitnikov, Yu. A. Dmitriev, and M. E. Kaymanov,Fizika Nizkikh Temper. 15, 639 (1989).
Yu. Kagan,J. Low Temp. Phys. 87, 525 (1992).
A. V. Ivliev, A. Ya. Katunin, I. I. Lukashevich, V. V. Sklyarevskii, V. V. Suraev, V. V. Filippov, and V. A. Shevtsov,JETP Lett. 36, 472 (1982).
A. S. Iskovskikh, A. Ya. Katunin, I. I. Lukashevich, V. V. Sklyarevskii, V. V. Suraev, V. V. Filippov, and V. A. Shevtsov,Sov. Phys. JETP 64, 1085 (1986).
F. Weinhaus and H. Meyer,Phys. Rev. B 7, 2974 (1973).
W. P. Haas, N. J. Poulis, and J. J. W. Borleffs,Physica (Utr.) 27, 1037 (1961).
R. F. Buzerak, M. Chan, and H. Meyer,J. Low Temp. Phys. 28, 415 (1977).
S. Washburn, R. Schweizer, and H. Meyer,J. Low Temp. Phys. 40, 187 (1980).
Chemical Kinetics, ed. by J. C. Polanyi, Baltimore, University Park Press, 1972.
A. Scherbakov, P. Malmi, and V. Shevtsov, Preprint RRC KI-5665/9, Moscow, 1993.
F. Schmidt,Phys. Rev. B 10, 4480 (1974).
J. G. Powles and J. H. Strange,Proc. Phys. Soc. 82, 6 (1963).
L. I. Amstutz, H. Meyer, S. M. Myers, and D. C. Rorer,Phys. Rev. 181, 589 (1969).
C. Ebner and C. C. Sung,Phys. Rev. B 5, 2625 (1972).
D. Zhou, C. M. Edwards, and N. S. Sullivan,Phys. Rev. Lett. 62, 1528 (1989).
D. Zhou, M. Rall, J. P. Brison, and N. S. Sullivan,Phys. Rev. B 42, 1929 (1990).
M. Rall, D. Zhou, E. G. Kisvarsanyi, and N. S. Sullivan,Phys. Rev. B 45, 2800 (1992).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Shevtsov, V., Scherbakov, A., Malmi, P. et al. Ortho-para conversion in solid hydrogen, catalyzed by molecular oxygen impurities. J Low Temp Phys 104, 211–235 (1996). https://doi.org/10.1007/BF00754095
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00754095