Hertz–Knudsen equation

Not to be confused with Knudsen equation.

In surface chemistry, the Hertz–Knudsen equation describes evaporation rates, named after Heinrich Hertz and Martin Knudsen.

Applications

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:[1][2]

Quantity Description
A Surface area (in m2)
N Number of gas molecules
φ Flux of the gas molecules (in m−2 s−1)
α Sticking coefficient of the gas molecules onto the surface, 0α1
p The pressure (in Pa)
M Molar mass (in kg mol−1)
m Mass of a particle (in kg)
kB Boltzmann constant
T Temperature (in K)
R Gas constant (J mol−1 K−1)

See also

References

  1. Kolasinski, Kurt W. (2012). Surface Science: Foundations of Catalysis and Nanoscience, Third Edition. p. 203. doi:10.1002/9781119941798.
  2. R. B. Darling, EE-527: Micro Fabrication, Virginia University (retrieved Feb. 9 2015).
This article is issued from Wikipedia - version of the 9/21/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.