### Particle Flux - an overview | ScienceDirect Topics

i.e. the particle flux is directly proportional to the particle density and the square root of the gas temperature, and is inversely proportional to the square root of the mass of the molecules. Pressure (P) is defined as the rate at which momentum is imparted to a unit area of surface. When a molecule bounces off a surface, there is a total change of momentum of 2 M c ¯. and so the rate of ...