As far as I understand, sigma profile in COSMO - RS is a probability distribution of screening charge density for certain molecular surface segment.

In COSMO - RS, molecular surface area is segmented into smaller surface segments and interactions between molecules are modelled via interaction of these segments.

However, I see that sigma profiles are made for whole molecules which doesn't make sense given their definition. Shouldn't sigma profile be made for certain molecular segment rather than whole molecule?

  • 2
    $\begingroup$ It is not a distribution of different interactions that can occur on a given segment, but the distribution of the interactions if you go through for the whole surface. So your first sentence causes the misunderstanding. $\endgroup$
    – Greg
    Mar 31 at 3:59
  • $\begingroup$ @Greg Yes, I found this definition in abstract of paper: Sigma-Profile Database for Using COSMO-Based Thermodynamic Methods, and it is wrong. I am reading Klamt now and there explanation is the same like what you said. $\endgroup$ Mar 31 at 13:58
  • 1
    $\begingroup$ I do not think it is a definition. Also, there is a book on COSMO-RS by Klamt if you can find it in your library. $\endgroup$
    – Greg
    Apr 1 at 15:30
  • $\begingroup$ Yes, that one is wrong. I've found what you said in Klamt. $\endgroup$ Apr 3 at 12:32


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