Radial distribution function: Difference between revisions

Revision as of 21:57, 2 March 2007

Revision as of 00:05, 13 March 2007

Line 13:

</center>

If <math>\phi(r)</math> would bewas zero for all r - i.e. if the molecules did not exert any influence on each other g(r) = 1 for all r. Then from (1) the mean local density would be equal to the mean density <math>\rho</math>: the presence of a molecule at O would not influence the presence or absence of any other molecule and the gas would be ideal. As long as there is a <math>\phi(r)</math> the mean local density will always be different from the mean density <math>\rho</math> due to the interactions between molecules.

When the density of the gas gets higher the so called low-density limit (2) is not applicable anymore due to the fact that the molecules attracted to and reppeled by the molecule at O also reppel and attract each other. The correction terms needed to correctly describe g(r) resemble the [[virial equation]], it is an expansion in the density: