Asymmetric fluid criticality. II. Finite-size scaling for simulations

The vapor-liquid critical behavior of intrinsically asymmetric fluids is studied in finite systems of linear dimensions L focusing on periodic boundary conditions, as appropriate for simulations. The recently propounded "complete" thermodynamic (L-->infinity) scaling theory incorporating pressure mixing in the scaling fields as well as corrections to scaling [Phys. Rev. E 67, 061506 (2003)] is extended to finite L, initially in a grand canonical representation. The theory allows for a Yang-Yang anomaly in which, when L-->infinity, the second temperature derivative (d(2)mu(sigma)/dT(2)) of the chemical potential along the phase boundary mu(sigma)(T) diverges when T-->T-c-. The finite-size behavior of various special critical loci in the temperature-density or (T,rho) plane, in particular, the k-inflection susceptibility loci and the Q-maximal loci - derived from Q(L)(T,<rho>(L))equivalent to<m(2)>(2)(L)/<m(4)>(L) where mequivalent torho-<rho>(L) - is carefully elucidated and shown to be of value in estimating T-c and rho(c). Concrete illustrations are presented for the hard-core square-well fluid and for the restricted primitive model electrolyte including an estimate of the correlation exponent nu that confirms Ising-type character. The treatment is extended to the canonical representation where further complications appear.