[gmx-users] Ryckaert-Bellemans and OPLS constants

[Kun-Lin Yang]

Dear All:

        Since R-B is defined in the "polymer convention" while GROMACS is
defined in the "protein convention".  Do I have to multiply every
coefficient Cn by (-1)^n  again or this has been done in the GROMACS.  In a
word, C1 should be 12.16 or -12.16 in GROMACS?

       Another problem happened when I tried to convert the OPLS potential
to R-B constants.  According to GROMACS manual page 62, C1= 0.5(3V3-V1), but
I found that I have to use -0.5(3V3-V1) to get good resutls.  Does anybody
ever wonder the same problem?

Thanks!

Kun-Lin, 4/22