Kirkwood–Buff integrals: From fluctuations in finite volumes to the thermodynamic limit
Jean-Marc Simon, Péter Krüger, Sondre K. Schnell, Thijs J. H. Vlugt, Signe Kjelstrup, Dick Bedeaux
Abstract
The Kirkwood-Buff theory is a cornerstone of the statistical mechanics of liquids and solutions. It relates volume integrals over the radial distribution function, so-called Kirkwood-Buff integrals (KBIs), to particle number fluctuations and thereby to various macroscopic thermodynamic quantities such as the isothermal compressibility and partial molar volumes. Recently, the field has seen a strong revival with breakthroughs in the numerical computation of KBIs and applications to complex systems such as bio-molecules. One of the main emergent results is the possibility to use the finite volume KBIs as a tool to access finite volume thermodynamic quantities. The purpose of this Perspective is to shed new light on the latest developments and discuss future avenues.