AMBER Archive (2005)

Subject: Re: AMBER: Any way to get different charge on same type atom

From: rpaduri_at_chem.wayne.edu
Date: Wed Nov 30 2005 - 18:37:13 CST

Dear Liu,

It looks like you have equivalenced your Carbons and all the Hydrogens in the
first stage fit of the resp. You only have to equivalence the CH2 Hydrogens and
that too in the second stage of your RESP fitting.
Hope this helps.

Best regards
Raviprasad Aduri

Quoting Jianzhong Liu <zhong_at_udel.edu>:

> Dear Users,
>
> I performed RESP charge derivation of a negative Gly with structure
> HN(-)-CH2-COO(-) with total charge -2.
>
> But the RESP always give me same charge on carbon, like following,
>
> no. At.no. q(init) q(opt) ivary d(rstr)/dq
> 1 7 -0.879760 -0.879760 -1 0.001129
> 2 6 0.134483 0.134483 -1 0.005967
> 3 1 -0.060721 -0.060721 -1 0.000000
> 4 6 0.134483 0.134483 -1 0.005967
> 5 1 -0.060721 -0.060721 -1 0.000000
> 6 1 -0.060721 -0.060721 -1 0.000000
> 7 8 -0.603522 -0.603522 -1 0.001635
> 8 8 -0.603522 -0.603522 -1 0.001635
>
> But I think the charge on Carbon atom should be different. Are there any ways
> to get different charge on these same type atoms.
>
> Jianzhong Liu
> ---------------------------------------
> Vita Brevis, Ars Longa

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