Diffusion of <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi mathvariant="normal">H</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span> adsorbed on single-walled carbon nanotubes

D. G. Narehood; J. V. Pearce; P. C. Eklund; P. E. Sokol; R. E. Lechner; J. Pieper; J. R. D. Copley; J. C. Cook

doi:10.1103/PhysRevB.67.205409

Diffusion of $H_{2}$ adsorbed on single-walled carbon nanotubes

D. G. Narehood, J. V. Pearce, P. C. Eklund, P. E. Sokol, R. E. Lechner, J. Pieper, J. R. D. Copley, and J. C. Cook

Phys. Rev. B 67, 205409 – Published 15 May 2003

Abstract

We report quasielastic neutron scattering measurements performed on $H_{2}$ adsorbed on single-walled carbon nanotubes. These measurements indicate that no quasielastic component to the scattering is present below 30 K. A quasielastic component is present at 30 K, indicating the onset of mobility of the adsorbed $H_{2} .$ This component to the scattering is well described by a liquidlike diffusion model, with a diffusion coefficient an order of magnitude greater than that of bulk liquid $H_{2} .$ The observed diffusion is consistent with two-dimensional diffusion on Grafoil and indicates that the adsorbed $H_{2}$ is leaving the groove sites of the nanotube bundles before diffusing on the outer surface of the bundles.