Quantum diffusion and catalyzed conversion of ortho-H-2 molecules in solid hydrogen



: Shevtsov V, Ylinen E, Malmi P, Punkkinen M

Publisher: AMERICAN PHYSICAL SOC

: 2000

Physical Review B

PHYSICAL REVIEW B

: PHYS REV B

: 62

: 18

: 12386

: 12394

: 9

: 0163-1829

DOI: https://doi.org/10.1103/PhysRevB.62.12386


The ortho-para conversion in solid hydrogen catalyzed by a small amount (similar to 10(-3)) of OZ impurities was studied to determine the temperature and concentration dependence of the ortho-H-2 diffusion coefficient. For T>5 K the diffusion coefficient has the activation-type dependence on temperature D(T) = 2 x 10(-11) exp(-92/T) cm(2) s(-1) and is independent of the ortho-Hz concentration C. For T<4 K this coefficient substantially changes its behavior and far C in the range 0.02-0.75 it can be described by the relation D(T,C) = 1 x 10(-21). T/C cm(2) s(-1). The results obtained are interpreted in terms of the quantum diffusion of ortho-H-2 molecules in sold hydrogen.



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