question about potential of different group

hi,
There are some questions on my project,

I build a DLC model (model-1) on diamon substrate by liquid quenching method,

and the model consists of three group: group-DLC, group-sub, group-boundary.
All the atoms is carbon, and when i depostion the DLC, the potential between all
atoms is tersoff.

I use the read_data commond read the data of model-1, to build the model-2. I want compute the interfacial strength of the group-DLC and group-sub with the commond ‘compute group/group’. But in model-2, the DLC departs from the sub. everything is same as the model-1, but the potential between the DLC and sub is morse(cutoff is 4),

By now, I know the reason of the DLC depart from the sub is the potential defference of the DLC and sub. In model-1, the potential of DLC and sub is tersoff. In model-2, the potenial of DLC and sub is morse.

My question is whether there is commond to compute the interfacial strength of different group? Only the commond ‘compute group/group’?
And when I build the model-1, how could I define the potential between DLC and sub?

And the data of the model-1 will be readed by model-2

Thanks
king
Harbin Institute of Technology
China