  In a theoretical study of gas adsorption on carbon nanotubes (CNT)
nonequilibrium processes of ionization, polarization, surface diffusion and
desorption of atoms are considered self-consistently. The approach is based on
Zubarev's method of nonequilibrium statistical operator and reaction-diffusion
theory. The set of nonlinear transport equations are obtained for the chosen
parameters of description: the average numbers of adsorbed atoms, ionized and
polarized atoms in the electromagnetic field of CNT, and the average number of
atoms desorbed from the CNT surface. Ab initio simulations are conducted for a
"gas-single wall carbon nanotube" system for gases of particular practical
interest: He and NO. The obtained values of adsorption energy reveal preferable
localization sites of absorbed He atoms as well as their dependency on
adsorption distances. A significant effect of NO adsorption on CNT electronic
properties is demonstrated. The effect of presence of vacancies on adsorption
nature is analyzed. It is shown that under the influence of vacancy formation
the CNT structure undergoes reconstruction that enables chemisorption of NO
molecules.
