bond-angle and bond-bond cross-terms

Dear All users

I should a force field for CaCO3 that includes these terms for bonded interaction:

Harmonic bond stretch term , harmonic cosine angle bending term , inversion term is of the

umbrella type , bond-angle and bond-bond cross-terms:

The last term is :

D(R1 - R1,0)(cos θ - cos θ0) + E(R2 - R2,0)(cos θ - cos θ0) + KR1R2(R1 - R1,0)(R2 - R2,0)

I can’t find this cross term in the manual, Is it possible to use this cross term in Lammps input?

If it is not in the class2 force field bonds,angles,etc, then
no, LAMMPS does not implement it. Note that anything
that involves bond/bond interactions would be in an angle
formula, the way LAMMPS handles it. There is an
angle_style table if your interaction can be pre-tabulated
as a function of theta.


Dear Steve

Thank you for your reply,