Dear All,

I am using LAMMPS version 7Aug2019.

I have used the group/group command to calculate the energy transfer between water (TIP4P model) and gold (with no charge) from the following command:

compute pair water group/group Au pair yes

compute kspace water group/group Au pair no kspace yes

I have implemented the following pair style and LAMMPS has been stopped due to error.

pair_style lj/cut/tip4p/long 2 1 1 1 0.1546 10 8.5

pair_coeff 1 1 0.00 0.00

pair_coeff 2 2 0.18 3.15

pair_coeff 1 2 0.00 0.0

pair_coeff 3 3 5.0 2.9

pair_coeff 1 3 0.0 0.0

pair_coeff 2 3 1.0 3.6

The error is as follows:

ERROR: Pair style does not support compute group/group (â€¦/compute_group_group.cpp:129)

As I have changed the pair style to a hybrid one as follows, the problem has been solved and the error did not appear anymore.

pair_style hybrid lj/cut/tip4p/long 2 1 1 1 0.1546 10 8.5 lj/cut 10

pair_coeff 1 1 lj/cut/tip4p/long 0.0 0.0

pair_coeff 2 2 lj/cut/tip4p/long 0.18 3.15

pair_coeff 1 2 lj/cut/tip4p/long 0.0 0.0

pair_coeff 3 3 lj/cut 5.0 2.9

pair_coeff 1 3 lj/cut 0.0 0.0

pair_coeff 2 3 lj/cut 1.0 3.6

Since I want to use â€ślj/cut/tip4p/longâ€ť for all interactions in the simulation, I will be pleased if someone can help me with this matter.

Is there any way to solve that?

Atom type 1 is Hydrogen, 2 is Oxygen and 3 is gold.

Best Regards,

Hamid