Buckingham + 18-6 Lennard-Jones

User discussions
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1

GROMACS version: 2021
GROMACS modification: No

Hi,

I would like to try some annealing on amorphos silica; in order to do so I either need a force field with triplets potential (which I rekon would be quite inefficient) or a pair potential that combines Buckingham and 18-6 Lennard-Jones.

Is it possible to do the latter in GROMACS, without recurring to tabulated potentials and/or to a 12-6 LJ approximation? I see I can define Buckingham parameters and combination rules, but I am not sure if (a) I can combine it with Lennard-Jones and (b) if I can define arbitrary powers for the repulsive part of LJ.

2

Hi,
The answer is to both question is no. The alternative is to use tabulated potential, but you have to down-grade to version 2018.
The tabulated potentials are not active from 2019 and they will probably come back in the future.

Kind regards
Alessandra

3

Hi,

I will try with an approximation then

Thanks