Pfeiffer Vacuum

1.2.5 Mean free path

The mean free path is the mean path length that a molecule traverses between two successive impacts with other molecules. It depends upon molecular diameter dm and temperature T in accordance with the following equation

Formula 1-8:

Mean free path

and is of significance for the various flow types of a gas in a vacuum.

Figure 1.4: Mean free paths

The table [1] below shows the product l ·p for various gases at 0 °C.

Table 1.5: Mean free paths of various gases at 0 °C

Page functions
  • How would you rate this page?


  • Recommend this page!


  • Social Networks:


Contact options

Our points of contact are available to you at any time:

Display contact options


You can use our contact form to send your request or concern directly to us.

Contact Form

Headquarters postal address

Pfeiffer Vacuum GmbH
Berliner Strasse 43
35614 Asslar

P.O. Box

Pfeiffer Vacuum GmbH
Postfach 1280
35608 Asslar

T +49 6441 802-0
F +49 6441 802-1202

Copyright © 2015 Pfeiffer Vacuum GmbH