[AMBER] MDGX charge fitting with some charges fixed or restrained

From: Luis Simon <lsimon.usal.es>
Date: Wed, 24 Feb 2021 09:34:30 +0100

Dear Amber users:

I wonder if there is any way of running mdgx charge fitting specifying a fixed charged for some of the atoms or group of atoms.

“MinimizeQ" keyword request to fix all the charges restraining those of the group of atoms specified by the following atom mask to zero… is ti possible to restraint it to a different value than 0?

I am trying to parametrize a set of molecules and I want to share the same charges with some of the atoms (just like amino acid backbone atoms share the same charges). MDGX allows this with the use of equalq keyword and the use of atom masks, but since the charges for all the molecules must be fitted simultaneously, my system run out of memory. A possibility would be to fit only a subset of the molecules (or even different subsets and use averages) and then transfer the charges of the backbone atoms to the rest of the molecules, for which the charges will be fitted separately. Is it possible to transfer them, fixing the charges of the common atoms?



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Received on Wed Feb 24 2021 - 01:00:02 PST
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