[gmx-users] qm mm and charges in GMX!
Samuel Silva Pita
samuelspita at ibest.com.br
Fri May 25 19:09:32 CEST 2007
Hi GMX'ers- specially Mark Abraham,
At the GROMACS compiled with MOPAC 7.0, I tried to simulate my drug, using
the QM/MM, at two *.itp files:
(a) At the first I put the CHELPG charge fitting.
(b) At the second itp file, I put zero charge since all the quantical or
semi-empirical methods compute the charge calculate (in principle, the
pontual charge at the quantical method is not necessary)
When I did the rdf calculate (i.e: (polar oxigen of my drug)-(water
oxigen))as expected in (a) we have the first (reffered to hydrogen bonds),
the second, three,... solvation layers while in (b) there are no the first
The questions are:
Is the pontual charge necessary at *.itp file when we have quantical
atoms- exactly knowing that quantical method, compute the charges?
How "hybrid GMX" interprets the atomic charges? Does GMX calculate the
atomic charges or we nedded to put it "by our hand"?
"Do not wear yourself out to get rich;do not trust your own cleverness.
Cast but a glance at riches, and they are gone, for they will surely sprout
wings and fly off to the sky like an eagle."(Proverbs 23:4-5)
SAMUEL SILVA DA ROCHA PITA MSc UFRJ-Braz
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