AMBER Archive (2003)

Subject: Re: AMBER: charge fitting

From: FyD (fyd_at_u-picardie.fr)
Date: Fri Nov 28 2003 - 12:45:21 CST

Dear itzi,

If you do want ot use the published RESP way for charge derivation, I think
there are a looot of errors in your inputs:

- you do not use qwt=.001 in your input2
- a heteroatom charge is not frozen in your input2 (the last atom)
- some hydrogens are not equivalenced and not frozeen in your input2... it means
to me that they belong to either N-H, C-H or O-H and then they should be frozen
or they belong to CH2 or CH3 and they should be equivalenced...
- If your charges are frozen I guess you do not need to use inter-conformational
restraints...
- 2 oxygens are equivalenced in input1 and only one of these 2 atoms is frozen
in the input2... I do not understand... ouf...
- etc etc...

If you do want to constraint this hydrogen 22 to zero, I would do it in the
first stage with inter-conformational restraints and freeze it in the second
RESP stage...

Best regards, Francois

F.-Y. Dupradeau
 --
The Scripps Research Institute, San Diego, CA
Faculte de Pharmacie, UPJV, Amiens, France
 --
http://www.u-picardie.fr/labo/lbpd/fyd.htm

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