I am doing some first-principle calculations on the thin film system like NiO/Ag(001). Now I need to calculate the surface energies of the system. What will be the formula for that and how I should proceed?
You can calculate surface energy of Ag(001) surface using the formula:
E_surf = (1/2A) * [E_slab - N * E_bulk]
where, E_surf is the surface energy, E_slab = total energy of a relaxed symmetric Ag(001) slab with several layers, E_bulk = total energy of bulk Ag unit cell, N = total number of number of bulk unit in the slab, A = surface area of Ag(001) slab.
You can calculate adsorption energy of NiO on Ag(001) surface using the formula:
where, E_ads = adsorption energy, E_NiO/Ag(001) = total energy of NiO/Ag(001) slab, E_Ag(001) = total energy of Ag(001) slab, mu_Ni and mu_O = chemical potentials of Ni and O respectively to be calculated as single atom energies, N_Ni and N_O are the number of Ni and O atoms on Ag(001) slab.