Thermodynamic equilibruim

1. Jan 22, 2007

Hot_phonon

Dear collegue,
I would like to ask you if some body know if there are explicit or implicit relation between "mean free path" and "thermal equilibruim"

Best regards.

2. Jan 25, 2007

LHarriger

The mean free path of a species in a gas decreases when pressure increases. Since pressure is a thermal equilibrium value we see that they are can be related.
Keep in mind that thermal equilibrium states that the rates at which the entropy increases in two systems in contact is the same with respect to a transfer of energy. This idea leads to our definition of temperature and consequently what you should be looking for is a way to write T as a function of l. The same should hold for diffusive equilibrium, ie: find a way to write chemical potential as a function of l.
I'm not saying this is always possible.

Last edited: Jan 25, 2007
3. Jan 25, 2007

StatMechGuy

I should imagine that the mean free path is in some way related to the speed of sound in the medium, which would then be related to how long it would take for a disturbance in the system to propagate throughout. But this would all give order of magnitude estimates, I can't think of anything explicit.

4. Jan 30, 2007

sicjeff

I believe this paper could be of interest to your discussion.

http://www.journals.uchicago.edu/ApJ/journal/issues/ApJ/v495n2/36196/36196.html [Broken]

Last edited by a moderator: May 2, 2017