- Number of Particles,
The partition function, , for a system of identical particles each of mass is given by
where is Planck's constant, is the temperature, is the Boltzmann constant and is the Hamiltonian corresponding to the total energy of the system. For a classical one-component system in a three-dimensional space, , is given by:
- is the de Broglie thermal wavelength (depends on the temperature)
- is the potential energy, which depends on the coordinates of the particles (and on the interaction model)
- represent the 3N position coordinates of the particles (reduced with the system size): i.e.