Ginzburg–Landau functional for liquid–vapor phase transition

Functional integration is used to find the partition function of a simple liquid and the Ginzburg–Landau functional for liquid-vapor phase transition. The short-range repulsive and long-range attractive parts of the particle-particle interaction potential are treated separately, and the expansion parameter is the ratio of the effective ranges of the repulsive and attractive forces. In addition, it is shown by means of the constructed functional that the well-known asymmetry of the liquid-vapor coexistence curve already appears in the framework of self-consistent field theory.