Liquid–gas critical phenomena under confinement: small-angle neutron scattering studies of CO2 in aerogel

Diffusion of interacting particles in discrete geometries: Equilibrium and dynamical properties

“…This can be seen as the result of the confinement, which prevents the formation of stable macroscopic phases [41][42][43]. We discuss how such behavior is reproduced in our model.…”

Supercritical Fluids in Confined Geometries

“…9.4) as well as individual fluids near the liquid-gas critical point as it can probe the local structure and thermodynamic properties of fluids in small pores with sizes of the order on 10-1000 Å. SANS was applied in [18,19] to study the temperature variation of the correlation length (ξ) of the density fluctuations as well as susceptibility (χ) of CO 2 confined in a random porous matrix of a silica aerogel with $96 % porosity, a surface area of 400 m 2 /g, a density of 0.1 g/cm 3 , and pore size distribution peaked around the nominal pore diameters 2R P $ 60-70 Å. Aerogel was obtained from Oscellus Technologies, Livermore, CA and shaped into a cylinder (17 mm OD, 10 mm length), which fit tightly into the SANS high-pressure cell (Sect. 4.2, Fig.…”

“…The lack of critical divergence of ξ CONF was interpreted in [18,19] as the result of the competition between the genuine critical fluctuations in the "core" of aerogel pores and critical absorption of CO 2 molecules on the silica strands of the aerogel, as both processes are characterized by a similar correlation length. The dilute quenched disorder induced by the host matrix suppressed density fluctuations in the critical region at all average densities of CO 2 studied.…”

Equation of State of a Cell Fluid Model with Allowance for Gaussian Fluctuations of the Order Parameter

“…The values of the quantities (0) and ′ , as well as Ξ ′ (27), (29), and their sum Ξ ′ = Ξ ′ + , are given in the Table for various . Hereinafter, the calculations are performed for Values of˜(0), ′ , and contributions from the quantities Ξ ′ and to the pressure of the system at different temperatures The value of the ratio 0 / is given in (2). For the quantities 0 and , taking (30) into account, we have 0 = 1.541, = 0.521.…”

“…We dedicate this paper to the 75th anniversary of Academician L.A. Bulavin, the outstanding Ukrainian physicist, who made a remarkable contribution to the development of the experimental base in the field of phase transitions and critical phenomena in simple and multicomponent liquid systems [1][2][3][4].…”