Monolayer sorption of neon in mesoporous silica glass as monitored by wide-angle x-ray scattering

Abstract

We report measurements of the X-ray scattering intensity as mesoporous silica glasses are filled with Neon. The intensity of the first peak in the liquid-like diffraction pattern increases non-linearly with mass adsorbed. We outline a simple model assuming that the major coherent contribution to the first peak in the scattering function S(Q) is due to interference from nearest-neighbour scatterers. This allows us to demonstrate an approach for surface area determination which does not rely on thermodynamic modelsand is therefore complimentary to existing methods. We also suggest that the overestimation of surface area by the traditional BET method may be resolved by using the capillary, and not the bulk, condensation pressure as the reference pressure, p 0 .Furthermore, the alternative analysis offers an insight into the atomic structure of monatomic sorption, which may be of use for further studies on materials with different surface properties.

Dimensional Reduction of Helium-4 Inside Argon Plated MCM-41 Nanopores

“…In this paper, we introduce a proposed solution which employs pre-plating MCM-41 nanopores with a single adsorbed layer of argon gas 45,46 , thereby allowing tunability of both the effective pore radius seen by helium atoms and the strength of the confinement potential. We combine experimental results employing N 2 and 4 He adsorption isotherms with large scale quantum Monte Carlo simulations to explore the atomic-scale structure within the pores and identify a promising region where the density of a central core of helium atoms may be manipulated upon filling.…”