In surface chemistry, the Hertz–Knudsen equation describes evaporation rates, named after Heinrich Hertz and Martin Knudsen.
Non-dissociative adsorption (Langmuirian adsorption)
The Hertz–Knudsen equation describes the sticking of gas molecules on a surface by expressing the time rate of change of the concentration of molecules on the surface as a function of the pressure of the gas and other parameters.
where:
References
Hertz–Knudsen equation Wikipedia(Text) CC BY-SA