Excess chemical potential

The excess chemical potential is defined as the difference between the chemical potential of a given species and that of an ideal gas under the same conditions (in particular, at the same pressure, temperature, and composition).The chemical potential of a particle species i {displaystyle i} is therefore given by an ideal part and an excess part. The excess chemical potential is defined as the difference between the chemical potential of a given species and that of an ideal gas under the same conditions (in particular, at the same pressure, temperature, and composition).The chemical potential of a particle species i {displaystyle i} is therefore given by an ideal part and an excess part. Chemical potential of a pure fluid can be estimated by the Widom insertion method. For a system of diameter L {displaystyle L} and volume V {displaystyle V} , at constant temperature : T {displaystyle T} , the classical canonical partition function Q ( N , V , T ) = V N Λ d N N ! ∫ 0 1 … ∫ 0 1 d s N exp ⁡ [ − β U ( s N ; L ) ] {displaystyle Q(N,V,T)={frac {V^{N}}{Lambda ^{dN}N!}}int _{0}^{1}ldots int _{0}^{1}ds^{N}exp} with s {displaystyle s} a scaled coordinate.