In physics (in particular in statistical mechanics), the Maxwell–Boltzmann
distribution , or Maxwell(ian) distribution , is a particular
probability distribution named after James Clerk Maxwell and Ludwig Boltzmann.
It was first defined and used for describing particle speeds in idealized
gases, where the particles move freely inside a stationary container without
interacting with one another, except for very brief collisions in which they
exchange energy and momentum with each other or with their thermal
environment. The term "particle" in this context refers to gaseous particles
only (atoms or molecules), and the system of particles is assumed to have
reached thermodynamic equilibrium.