Radial distribution function: Difference between revisions

Revision as of 22:41, 7 September 2007

Revision as of 15:27, 15 November 2007

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If <math>\phi(r)</math> was 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 thatbecause the molecules attracted to and repelled by the molecule at O also repel and attract each other. The correction terms needed to correctly describe g(r) resembles the [[virial equation]], it is an expansion in the density:

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