Talk:Radial distribution function

In the near future I will be adding the formal derivation of g(r) in the article... 14-02-2007 - Joris Kuipers
Nice, I am thinking that maybe some information about/from experiments might be useful. Like Alan Sopers articles. omermar 30/05/07

Eq. 13

The line below equation 13 reads: "In fact, equation 13 gives us the number of molecules between r and r + d r about a central molecule." However, it looks to me that equation 13 gives us the total number N of the molecules of the system, .... Lwzhou (talk) 12:22, 6 October 2008 (UTC)lwzhou[reply]

As I understand, the current version of eq. 13 gives the TOTAL number of molecules in the SYSTEM (since it is from zero to infinity).
I suggest the following correction:
1) Make the range of the integral from r1 to r2.
2) Add/modify the text: Eq. 13 gives the number of molecules in the solvation shell of a central molecule, when r1 & r2 are picked at consecutives minimums of the RDF function. For example - for the number of molecules in the first solvation shell, r1=0 & r2 is picked at the second minimum of g(r).
For water, when r1=0 & r2=3.5 Angstroms, then N ~ 4.5 molecules.

omermar --http://www.fh.huji.ac.il/~omerm 07:56, 7 October 2008 (UTC)[reply]

Just a short comment: as far as I understand it in eq. 13 g(r) does not give the number of molecules between r and r+dr. You would still have to multiply it with the particle density and 4Pi r^2. Suggestions 1) and 2) of above are still correct. —Preceding unsigned comment added by 141.24.104.201 (talk) 14:10, 11 November 2008 (UTC)[reply]

Is it true that (Rou g(r) 4 Pi r^2 dr) gives the the number of molecules between r and r+dr. Is g(r) here in Eq. 13 means the probability finding a molecule at the distance r from a center molecule, and is often called pair distribution function, while (Rou g(r) 4 Pi r^2 dr) called radial distribution function? It seems that different sources give different definitions of PDF and RDF.