[gmx-users] OPLSAA

Eric Smoll ericsmoll at gmail.com
Sun Oct 19 19:43:58 CEST 2014

Hello Gromacs users,

Here is a quote from a JPCB paper with over 500 citations:

"In fact, in the specification of the OPLS-AA force field, sites within the
same molecule separated by *more than* three bonds interact by
Lennard-Jones and electrostatic potentials scaled by a factor of 0.5"

Am I correct in assuming that "separated by more than three bonds" is a
typo and should "separated by three bonds"? I have read the original OPLS
reference (Jorgensen 1996) and it says:

"it was found to be necessary to scale the 1,4-nonbonded interaction to
permit use of the same parameters for inter- and intramolecular
interactions. Scaling factors fij = 1/2 for both the coulombic and
Lennard-Jones interactions emerged a  the final choice..."

There is no mention of this phrase in the additions and corrections

Gromacs only scales the 1-4 interactions, not all nonbonded interactions
beyond three bonds, correct?


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