Ney
E_KS is the total energy of the electron system for
each nuclear snapshot. The total energy (pot+kin) of
the electrons represents the effective potential
energy for the nuclear dynamics, in the adiabatic
decomposition of both dynamics. It is thus the
relevant potential energy surface for the nuclear
dynamics, hence the name (I don't think it is
misleading).
(the springs etc of the mentioned examples are
model descriptions of how this total energy of
the electrons would change with nuclear positions:
the empirically parametrised atomic *potentials* in
empirical MD)
It is Born-Oppenheimer, as Andres was saying.
Emilio
On Feb 18 2011, N H wrote:
In molecular dynamics all chemical bonds are represents - I mean
represented - by springs ... so it is obvoious that what dou you have in
the and is a potential energy! But that is not true if if you are
comparing quantum levels ... it doesn't matter if HF, CI or KS ones -
because in this energies what you have are components of the electronic
kinetic energy plus all the potential terms. And by potentiual terms I
mean the electrostatic interactions of the electrosn with their couter
parts in the system plus the interactions with the external field!
In this sense ... calling the E_KS energy as the "potential energy" is
simply misleading!
Cheers
Ney
--
Emilio Artacho
Department of Earth Sciences, University of Cambridge
Downing Street, Cambridge CB2 3EQ, UK
Tel. (+44/0) 1223 333480, Fax (+44/0) 1223 333450
[email protected], http://www.esc.cam.ac.uk/~emilio
