  We present a formalism for coupling a density functional theory-based quantum
simulation to a classical simulation for the treatment of simple metallic
systems. The formalism is applicable to multiscale simulations in which the
part of the system requiring quantum-mechanical treatment is spatially confined
to a small region. Such situations often arise in physical systems where
chemical interactions in a small region can affect the macroscopic mechanical
properties of a metal. We describe how this coupled treatment can be
accomplished efficiently, and we present a coupled simulation for a bulk
aluminum system.
