On Fri, 18 Feb 2011, N H wrote:
Hi all, Are you sure it is correct to say that E_KS is the system's "potential" energy? What about the kinetic energy use to calculate the Kohn-Sham levels? Cheers NH
This is again terminology: Yes, the potential energy of your system includes the kinetic energy of the electrons. When you do molecular dynamics with a parameterized empirical potential, your potential energy function also includes the kinetic energy of electrons in an implicit way.
The kinetic energy of electrons is needed to calculate the potential energy surface which determines the forces on atoms. This is just Born-Oppenheimer approximation. Your kinetic energy is purely ionic if you want to study the dynamics of ions. Everything else goes to the (effective, if you wish) potential energy.
Andres Aguado
