English

Work relation for determining the mixing free energy of small-scale mixtures

Statistical Mechanics 2022-03-01 v2 Chemical Physics

Abstract

In thermodynamically characterizing a mixture comprising a finite number of molecules, we consider two kinds of protocol for producing a mixture from a pure substance. The first is a single alchemical operation, whereas the second is a series of processes with feedback control in information thermodynamics and conventional mixing with semipermeable membranes. A comparison of the two numerically determined free-energy changes provides a combinatorial factor that indicates the indistinguishability of the molecules and an alternative Jarzynski equality. The comparison also uncovers a work relation for determining the mixing free energy without using semipermeable membranes. We demonstrate a numerical calculation of applying the work relation to a mixture of argon and krypton. The mixing free energy clearly shows the characteristics of liquid--vapor transition.

Keywords

Cite

@article{arxiv.2111.06110,
  title  = {Work relation for determining the mixing free energy of small-scale mixtures},
  author = {Akira Yoshida and Naoko Nakagawa},
  journal= {arXiv preprint arXiv:2111.06110},
  year   = {2022}
}

Comments

17 pages, 14figures