From: David Pearlman <>
Date: Tue 23 Apr 2002 15:05:12 -0500


In general, INTPRT should be set to 5 and NCORC = 1. Other option
values for these variables would only be used in select,
unusual cases. For a standard free energy run, you should set
them to 5 and 1, respectively. This is the recommendation of the
J. Chem. Phys. paper you cite.


Sophia Kondratova wrote:
> Hello,
> I have a question regarding the INTPRT flag. Normally, when doing FEP, should
> the INTPRT be set to something other than zero in order to calculate the
> intra-perturbed group contributions? From reading the J.Chem.Phys.94(6)paper
> (The overlooked bond-stretching contribution in free energy perturbation
> calculations), where PMF calculations together with SHAKE were used to
> calculate these intra-perturbed group contributions, it seems to me that these
> contributions should always be calculated and therefore when performing FEP,
> using SHAKE and setting NCORC = 1 (PMF on) would include these contibutions.
> What sort of calculations occur when INTPRT is set to something other than
> zero while the PMF is turned off? Are the intra-perturbed group contributions
> still being calculated? When should PMF be turned on and what should INTPRT be
> set while doing free energy calculations. I did read the manual and the paper
> that I have mentioned but I would still appreciate some information on these
> topics.
> Thanks in advance
> Sophia Kondratova
> Chemistry Graduate Student
> University of New Brunswick
> Fredericton, Canada
Received on Tue Apr 23 2002 - 13:05:12 PDT
Custom Search