AMBER Archive (2009)

Subject: Re: [AMBER] R.E.D. resp error

From: FyD (fyd_at_q4md-forcefieldtools.org)
Date: Thu Nov 12 2009 - 23:36:44 CST

Dear S. Bill,

> I am trying to calculate the atomic charge of one ligand using
> R.E.D. resp program. I have optimized my molecule using
> #P HF/6-31G* Opt=Tight GFInput GFPrint SCF(Conver=8) Test
> BUT I FREEZED some atoms during my optimization.

No problem we use geometry optimization with (dihedral) constraint(s).
(In this case, the ModRedundant mode in Opt is used).

> When I tried to use R.E.D. it gave me error "Invalid optimization output"
> How can I treat this problem?

First, you need to have the same atom order in each P2N file & QM
output used in the charge derivation.

Second, are you sure the optimization job has converged ?
R.E.D. checks that by looking for "Stationary point found" and "Normal
termination of Gaussian" in the QM output.

You can check that manually using:
egrep "Stationary point found|Normal termination of Gaussian"
Your-Gaussian-output

If "Stationary point found" is not found this means your QM job did
not converge; mainly because of the use of the Opt=Tight keyword.
Re-run the job using the best intermediate "Standard orientation" (-
or the last one).

tail Your-Gaussian-output
should report something like "Error... in termination ..." when your
QM job did not converge...

regards, Francois

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