The Boltzmann equation is given by (Ref.1 Eq 1 Chap. IX)

where Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle }
is an external force and the function C() represents binary collisions.
See also
References
- Sybren R. De Groot and Peter Mazur "Non-Equilibrium Thermodynamics", Dover Publications