Isotope effect on adsorbed quantum phases: Diffusion of H2 and D2 in nanoporous carbon

Journal Article · Tue Jan 01 04:00:00 EST 2013 · Physical Review Letters

DOI:https://doi.org/10.1103/PhysRevLett.110.236102· OSTI ID:1087032

Contescu, Cristian I ^[1]; Zhang, Hongxin ^[1]; Olsen, Raina J ^[1]; Mamontov, Eugene ^[1]; Morris, James R ^[1]; Gallego, Nidia C ^[1]

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1. ORNL

Quasielastic neutron scattering of H2 and D2 in a nanoporous carbon at 10 40 K demonstrates extreme quantum sieving, with D2 diffusing up to 76 times faster. D2 also shows liquid-like diffusion, while H2 exhibits distinct solid-type diffusion. The onset of diffusion occurs at 22 25 K for H2 and 10 13 K for D2. We show this difference may be explained by different commensurability of the two adsorbed isotopes with carbon substrate. We further observe that H2 and D2 have identical thermal de Broglie wavelength at their respective onset temperatures, and correlated with the dominant pore size.

• Research Organization: Oak Ridge National Laboratory (ORNL); Spallation Neutron Source
• Sponsoring Organization: SC USDOE - Office of Science (SC)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1087032
• Journal Information: Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 23 Vol. 110; ISSN 0031-9007
• Country of Publication: United States
• Language: English

Related Subjects

Diffusion
Extreme confinement
Porous carbon
Quantum sieving
Quasielastic scattering