Isotope Effect on Adsorbed Quantum Phases: Diffusion of ${\mathbf{H}}_{2}$ and ${\mathbf{D}}_{2}$ in Nanoporous Carbon

Isotope Effect on Adsorbed Quantum Phases: Diffusion of $H_{2}$ and $D_{2}$ in Nanoporous Carbon

Cristian I. Contescu, Hongxin Zhang, Raina J. Olsen, Eugene Mamontov, James R. Morris, and Nidia C. Gallego

Phys. Rev. Lett. 110, 236102 – Published 7 June 2013

Abstract

Quasielastic neutron scattering of $H_{2}$ and $D_{2}$ in the same nanoporous carbon at 10–40 K demonstrates extreme quantum sieving, with $D_{2}$ diffusing up to 76 times faster. $D_{2}$ also shows liquidlike diffusion while $H_{2}$ exhibits Chudley-Elliott jump diffusion, evidence of their different relationships with the local lattice of adsorption sites due to quantum effects on intermolecular interactions. The onset of diffusion occurs at 22–25 K for $H_{2}$ and 10–13 K for $D_{2}$ . At these temperatures, $H_{2}$ and $D_{2}$ have identical thermal de Broglie wavelengths that correlate with the dominant pore size.

Received 6 February 2013

DOI:https://doi.org/10.1103/PhysRevLett.110.236102

Authors & Affiliations

Cristian I. Contescu^1,*, Hongxin Zhang¹, Raina J. Olsen¹, Eugene Mamontov², James R. Morris¹, and Nidia C. Gallego¹

¹Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
²Neutron Scattering Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA