how to obtain the adhesion energy of A/B interface?

Hi, all,
In my study, there are two bulk materials, which are adhered together by depositing A on the suface of B. I want to calculate the adhesion energy of A/B interface, W, which is defined as:
W=(E(A)+E(B)- E(A/B))/S, where E(A), E(B), and E(A/B) are the energies of the isolated A and B and the A/B, respectively, and S is the surface-interface aera. With using LAMMPS, E(A/B) could be directly obtained as the energy of the whole system. My question is: how to directly obtain E(A) and E(B) in LAMMPS? Is there any commands which could be used?
Any reply will be highly appreciated.

Best,
Justin

Hello Justin,

If you need to calculate energy of particular group of atoms, you can declare atoms in material A as one group and B as another and use COMPUTE command to calculate the energy of each group.
That is how i do it, others may use different methods.

Regards,
Rohit.

Hi Justin,

By definition you have to use “isolated” A and B, so that in your simulation box you have to remove slab B when calculating E(A) and vice versa. Final potential energies from three independent runs will give you the numbers you need.
Ray

Hi, Ray,
Your explanation sounds great. I have tried to obtain the potential energy of “isolated” A and B. I have a little doubt about this question: is the potential energy of “isolated” A obtained immediately when B is removed? or is it obtained after a long enough time to make A relax?

Best,
Justin