Re: [AMBER] frcmod format file

From: David A Case <>
Date: Wed, 10 Sep 2014 07:43:47 -0400

On Tue, Sep 09, 2014, Maria Osorios wrote:
> In Amber the angles, dihedral and bonds are described by two characters.
> I need to define a structure using three characters per atom, for example:
> C23 is the carbon twenty three

Remeber to distinguish between atom names and atom types. Atom names can be
up to four characters long. Atom types can only be two characters long.
Even though you may have 23 carbon atoms (each requiring a separate name), it
would be most unusual to need 23 separate carbon types.

Parameter files deal with atom types, not atom names. Since each character
can be upper or lower case, or a digit, you have (26+26+10)**2 = 3844 possible
atom types.


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Received on Wed Sep 10 2014 - 05:00:02 PDT
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