AMBER Archive (2006)

Subject: Re: AMBER: dihedral parameters

From: Carlos Simmerling (
Date: Sat Feb 04 2006 - 11:30:27 CST

if you look at the energy function, the angle is multiplied by
the periodicity. A period of 0 means constant energy.
To remove the 1-4 you need to remove the dihedrals altogether.
there may be other ways if you want to manually modify the prmtop.

richard dimelow wrote:
> dear all
> the dihedral parameters are listed in the .dat files as IDIVF
> PK PHASE PN. Could some one tell me what happens if i set PN (the
> periodicity value) to zero. Does this turn off the 1-4 interactions
> between atoms 1 and 4 in the dihedral, for example?
> cheers
> rich
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