The characteristic state function or Massieu's potential in statistical mechanics refers to a particular relationship between the partition function of an ensemble.

In particular, if the partition function P satisfies

in which Q is a thermodynamic quantity, then Q is known as the "characteristic state function" of the ensemble corresponding to "P". Beta refers to the thermodynamic beta.

Examples

• The microcanonical ensemble.

• The canonical ensemble hence, its characteristic state function is the Helmholtz free energy.

• The grand canonical ensemble, so its characteristic state function is the Grand potential.

• The isothermal-isobaric ensemble so its characteristic function is the Gibbs free energy.

State functions are those which tell about the equilibrium state of a system

References