English

Mini-grand canonical ensemble: chemical potential in the solvation shell

Statistical Mechanics 2017-11-22 v1

Abstract

Quantifying the statistics of occupancy of solvent molecules in the vicinity of solutes is central to our understanding of solvation phenomena. Number fluctuations in small `solvation shells' around solutes cannot be described within the macroscopic grand canonical framework using a single chemical potential that represents the solvent `bath'. In this communication, we hypothesize that molecular-sized observation volumes such as solvation shells are best described by coupling the solvation shell with a mixture of particle baths each with its own chemical potential. We confirm our hypotheses by studying the enhanced fluctuations in the occupancy statistics of hard sphere solvent particles around a distinguished hard sphere solute particle. Connections with established theories of solvation are also discussed.

Keywords

Cite

@article{arxiv.1706.08998,
  title  = {Mini-grand canonical ensemble: chemical potential in the solvation shell},
  author = {Purushottam D. Dixit and Artee Bansal and Walter G. Chapman and Dilip Asthagiri},
  journal= {arXiv preprint arXiv:1706.08998},
  year   = {2017}
}