The Maxwell-Boltzmann statistic or distribution (not to be confused with the other Maxwell-Boltzmann distribution) is a real, continuous Probability distribution that describes the behavior of a system of classical particles in thermal equilibrium. Its Probability density function is
is the average number of particles in the -th single-particle state of energy , is the system chemical potential, is the inverse temperature, with the Boltzmann constant and the temperature, and is the fugacity. The normalization constant is
This distribution is closely related to its quantum equivalents, the Fermi-Dirac distribution and the Bose-Einstein distribution. These converge to the Maxwell-Boltzmann statistic at high temperature.