Dear AMBER commmunity,
I'm not quite sure what's the proper way to derive charges by RESP on ligand
for ff99.
1) Do I need to minimize the structure (or hydrogens?) What level of theory?
HF/6-31G*?
(in this case I have an x-ray stucture of the inhibitor complexed with
receptor; I add hydrogens in INSIGHT II)
2)As James Caldwell wrote:
#HF/6-31G* SCF=tight Test Pop=MK iop(6/33=2) iop(6/42=6) opt
Is the tight convergence crucial (or better)? How much?
>>>>>iop(6/42=6) calculate 6 points per unit area for the ESP, default is 1
(I have no idea what the unit area
actually is)
Is this iop necessary? I hadn't seen this before........
Is multiple-conformation charge-fitting recommended? (generally or for my
case?) How many conformations do I need? How do I geneate them?
Thanks for your answers.
All the best,
Martin
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Martin Lepsik, PhD student Phone: +420/2/20183-540, Fax:
+420/2/20183-292
Dept. of Theor Chem & Center for Complex molecular Systems and Biomolecules
Institute of Organic Chemistry and Biochemistry (IOCB)
Flemingovo nam 2,
Czech Academy of Sciences,
166 10, Prague 6,
Czech Rep.
URL: www.uochb.cas.cz/~teochem
Received on Tue Feb 04 2003 - 09:34:57 PST
