Re: AMBER: How to apply OPLS force field?

From: David A. Case <>
Date: Thu, 15 Jul 2004 10:04:22 -0700

On Thu, Jul 15, 2004, Wu Lei wrote:

> i've tried both method,and it works! but new problem arised, when using
> "saveamberparm" command, new error message has appeared:
> For atom .... Could not find type: CK
> ...
> but there is { "CK" "C" "sp2" } in addatomtypes section in leaprc file.
> is any where else should i add the atomtype definition in leap input files?

I am assuming that you made up your own leaprc file, since there is nothing
in the distribution for the opls parms.

I think you will have to also edit the opls_parm.dat file to remove the STDA
and STUB nonbond sets, leaving only the OPLS one. This file pre-dates the
introduction of LEaP, which really allows only one non-bonded set; (earlier
code allowed the user to specify which set to use.)

As I mentioned before, it has probably been more than a decade since any
Amber developer used this force field, so you will need to work very
carefully, and verify for yourself that things are working. I would recommend
starting off with a small system, so that you can check the results manually.

.....good luck...dac

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Received on Thu Jul 15 2004 - 18:53:00 PDT
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