Nonuniform properties of atomic fluid in electrical field

Wetting in the presence of the electric field: The classical density functional theory study for a model system

“…After switching on the electric field |E| > 0, one can calculate within the framework of the quantum-mechanical perturbation theory with respect to the interaction with the field the second-order results for the energy of a single atom, E N =1 , or of a group of two atoms at (a sufficiently large) distance R = |R 12 |, E N =2 , see Appendix and Ref. 18.…”

“…Bearing in mind that we are interested in the lowest term in |E| only, the orientational averages can be done using a cumulant expansion. After straightforward but cumbersome calculations (for details see Appendix) we find the second virial coefficient of the two-level-atom fluid [18]:…”

“…( 3) with V (r) = 0 the bulk properties, when ρ(r) = ρ, we find the critical density η c ≈0.130 44, the critical temperature τ c (E) ≈ 0.001 965 18ℵ 2 (1 + 2ℵ 2 E 2 ), and the critical pressure π c (E) ≈ 0.000 092 02ℵ 2 (1 + 2ℵ 2 E 2 ) of the fluid at hand; here we have introduced the dimensionless variables η = ρv, τ = T /(E 1 − E 0 ), π = pv/(E 1 − E 0 ), see Ref. 18. Within the adopted approach, the critical density is independent of the field but the critical temperature and the critical pressure increase by the factor 1 + 2ℵ 2 E 2 .…”

“…Equations (A4), (A7), (A9) give the explicit result for b 1 [18] and the formula for b 2 as a two-fold integral [18] which besides the integration over R = |R 12 | contains the integration over θ R12 , see Eq. (A7).…”