From: Sophia Kondratova <>
Date: Tue 23 Apr 2002 15:23:36 -0300


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

Thanks in advance

Sophia Kondratova
Chemistry Graduate Student
University of New Brunswick
Fredericton, Canada
Received on Tue Apr 23 2002 - 11:23:36 PDT
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