[gmx-users] question about the Silicon force field in gromacs

[Baofu Qiao]

Dear prof. van der Spoel,

I am planning to study the Silicon crystalline. But I have one question
about the force field of silicon. In the original paper, (E. J. W.
Wensink, et al., Properties of Adsorbed Water Layers and the Effect of
Adsorbed Layers on Interparticle forces by Liquid Bridging,  Langmuir,
2000, 16, 7392-7400.), the LJ parameters are given as C6=0.22617*10^(-2)
kJ nm^6/mol, and C12=0.22191*10^(-4) kJ nm^12/mol.
While in ffG53a6nb.itp,  C6= 0.01473796, C12= 2.2193521e-05. The value
of C6 is different, with the same value of C12. Is there an error in the
inconsistence, or I missed something?

PS: in ffoplsaanb.itp, sigma=3.38550e-01, epsilon= 2.44704e+00, which is
consistent with the ffG53a6nb.itp.

Since it is you who added the force field of silicon, and you have one
related publication (D. van der Spoel, et al.,  Lifting a Wet Glass from
a Table: A Microscopic Picture, Langmuir, 2006, 22, 5666.), I think you
might be able to give me some help. Thanks a lot!

best wishes,
Baofu Qiao