I’m trying to simulate a zeolite structure (MFI) with the cvff force field.

The equation to calculate nonbonded interactions for this force field is as follows:

E = Aij/r^12 - Bij/r^6

where Aij = sqrt( Ai * Aj )

Bij = sqrt( Bi * Bj )

Looking in lammps documentation I couldn’t find a pair style that uses this equation. The only that comes close is pair_style lj/cut:

E=4ε[(σ/r)¹²-(σ/r)⁶]

I’m looking for suggestions on how to handle this. Should I try to convert parameters to fit to the equation that lammps uses?

I'm trying to simulate a zeolite structure (MFI) with the cvff force

field.

The equation to calculate nonbonded interactions for this force field is

as follows:

E = Aij/r^12 - Bij/r^6

where Aij = sqrt( Ai * Aj )

Bij = sqrt( Bi * Bj )

Looking in lammps documentation I couldn't find a pair style that uses

this equation. The only that comes close is pair_style lj/cut:

E=4ε[(σ/r)¹²-(σ/r)⁶]

I'm looking for suggestions on how to handle this. Should I try to convert

parameters to fit to the equation that lammps uses?

they are the same equation, just different partitioning of the constants.

for as long as Ai, Aj, Bi, and Bj are != 0, you can convert between them.

this is middle-school level calculus.

axel.