[gmx-users] About cutoffs for OPLSAA

[sujithkakkat .]

Dear all,

    I want to study a system consisting of water, methane and CO2. I will
use TIP4P/Ice , OPLSAA and EPM2 models respectively for the components .


    My problem is, how do I make a choice of the cutoff lengths, for a
system which uses different molecular models which were parametrized
individually at different cutoff values.

    I am not sure whether I should use  the LJ and Coulomb cutoff values to
the OPLSAA forcefield which I would be using. The paper about EPM2
(J.Phys.Chem. Vol. 99, N0.31, 1995) mentions cutoff values of 1nm, whereas
the article (J. Chem. Phys. 122, 234511,2005) about TIP4P/Ice model
mentions an  LJ cutoff value of 0.85nm. To add to my confusion, in Justin's
manual on free energy calculation which used OPLSAA forcefield with TIP3P
water model,  cutoff lengths 1.0 and 0.9nm are used for coulombs and vdW
interactions, whereas, article (J. Phys. Chem. B 2012, 116, 14115-14125)
which uses OPLSAA again but with a TIP4P-Ew model for water uses slghtly
different values (rvdw=0.95 and coulomb = 0.85nm) .

Please let me know what you think.


Regards,

Sujith.