Pair_modify in hybrid pair_style

Dear all,

I am using a hybrid pair_style and defining sigma(ij) and epsilon(ij) parameters of VDW by mix arithmetic pair_modify as follow:

pair_style hybrid lj/cut/coul/long 14 lj/charmm/coul/long 12 14
pair_modify pair lj/cut/coul/long mix arithmetic tail yes
pair_modify pair lj/charmm/coul/long mix arithmetic tail yes

I receive the error of “All pair coeffs are not set”. Could you please guide me how I can define sigma and epsilon parameters between atoms which have different styles of lj/cut and lj/charmm (by mix arithmetic)? Thank you so much.

Best regards,

Mina

You need to provide your (presumably incorrect) pair coeff commands.

Also re:SHAKE for more than 4 atoms or bonds. LAMMPS does not
allow for SHAKE in that manner. You might check out fix rigid/small.

Steve