| 2:37:36 AM PDT - Thu, Oct 11th 2012 |
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Quote:Bert Oct 9th 1:16 pmI have no clue what RESPA stands for and can't find anything online about it either.
Sorry for the typo, of course not RESPA, but RESP.
Quote:Bert Oct 9th 1:16 pmI guess you want to tell ESP to give an atom a minimum or maximum charge. This is not available in NWChem's ESP module. You probably could write the code yourself, modifying ESP.
I would like to do as described in the article, which introduced the RESP J Phys Chem 1993, v.97. p.10269
It describes three models with penalty functions:
(model 1) x2 = a (q0 – q)2
(model 2) like (1) but q0=0
(model 3) x2 = a ((q2 +b2)1/2 – b)
My first guess is that there is no control in NWChem for q0. So I can use (model 2) and (model 3), but not (model 1). Is this true?
I see that the directive "constrain" does not provide the exact charges.
So my second assumption is that "constrain" not the charges fixing, but really is the (model 1). May be this true?
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