Brey Abalo, José JavierGarcía de Soria Lucena, María IsabelMaynar Blanco, Pablo2021-01-262021-01-262020Brey Abalo, J.J., García de Soria Lucena, M.I. y Maynar Blanco, P. (2020). Self-diffusion in a quasi-two-dimensional gas of hard spheres. Physical Review E, 101 (1), 012102.2470-00452470-0053https://hdl.handle.net/11441/104243A quasi-two-dimensional system of hard spheres strongly confined between two parallel plates is considered. The attention is focused on the macroscopic self-diffusion process observed when the system is seen from above or from below. The transport equation, and the associated self-diffusion coefficient, are derived from a Boltzmann-Lorentz kinetic equation, valid in the dilute limit. Since the equilibrium state of the system is inhomogeneous, this requires the use of a modified Chapman-Enskog expansion that distinguishes between equilibrium and nonequilibrium gradients of the density of labeled particles. The self-diffusion coefficient is obtained as a function of the separation between the two confining plates. The theoretical predictions are compared with molecular dynamics simulation results and a good agreement is found.application/pdf9 p.engAttribution-NonCommercial-NoDerivatives 4.0 Internacionalhttp://creativecommons.org/licenses/by-nc-nd/4.0/info:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccesshttps://doi.org/10.1103/PhysRevE.101.012102