Publication Type
Journal
Journal Name
Physical Review Letters
Publication Date
Page Number
236102
Volume
110
Issue
23
Abstract
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.
