# Help,how can I get the potential energy of each atom in a structure using DFT package

 P: 6 I am a freshman in DFT calculation. I don't understand the DFT method clearly,but I want to use DFT to do some calculations. My question is that how how can I get the potential energy of each atom in a structure using DFT package ,which I have done by using classical MD method in Lammps(the command: compute 1 all pe/atom ,Lammps manual :The per-atom energy is calculated by the various pair, bond, etc potentials defined for the simulation. If no extra keywords are listed, then the potential energy is the sum of pair, bond, angle, dihedral,improper, and kspace energy.). I want to know how can I do such a calculation.Please give some suggestions.
 P: 6 I now know that i can get the force F of each atom from the results of vasp relaxation calculation .In the classical theory,F= dU/dr(U is the potential energy),,so if it's possible to get the potential energy from the VAsp or other package calculation?
 P: 252 The notion of energy per atom is ill defined for a non-crystalline material. IF you are modelling a crystal , you simply divide the total energy by the number of unit formulas of the crysta.
P: 6
Help,how can I get the potential energy of each atom in a structure using DFT package

 Quote by Useful nucleus The notion of energy per atom is ill defined for a non-crystalline material. IF you are modelling a crystal , you simply divide the total energy by the number of unit formulas of the crysta.

Thank you for your reply,Why is it ill defined for non-crystalline material? And you may misunderstand my question. I want to get the relative potential energy of each atom in a structure,not energy per atom.