Re: [AMBER] Modifying Parameters in parm7

From: David A Case via AMBER <>
Date: Fri, 30 Sep 2022 20:52:40 -0400

On Fri, Sep 30, 2022, Collin Nisler via AMBER wrote:
>So, for example, if you have a dihedral with 3 terms, having multiplicity
>1, 2, and 3, the 4 atoms forming this dihedral will be listed 3 times,
>each with a different index pointing to the specific parameters for each
>term (and each multiplicity being listed as -1, -2, and -3). Is this a
>correct interpretation? Does it matter in what order the dihedrals are
>listed in the DIHEDRALS_WITHOUT_HYDROGEN section as long as the index for
>the associated parameters is correct? Thanks very much.

Above is close, but not completely correct. The final multiplicity (3 in
you example) should be positive.

For details go here:
Scroll down to item 6 ("input for dihedral parameters"), and see the entry
about PN.

(You can get there from by selecting File Formats -> Force Field
parameter specifications -> main parameter set.)

It's also worthwhile to look at files in $AMBERHOME/dat/leap/parm (such as
parm10.dat) for examples.

....hope this helps....dac

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Received on Fri Sep 30 2022 - 18:00:03 PDT
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