Abstract

Boundary conditions imposed on a local system joined to a larger substrate system often introduce unphysical reflections that affect the calculation of physical properties. In quantum mechanical systems, they affect the calculation of electronic wave functions, eigenstate energies, densities of states, and charge densities. These problems persist in atomic cluster and surface slab calculations alike. However, electron states in physical systems do not exhibit such reflective properties: instead, these wave functions propagate smoothly across the location where the calculation imposes an artificial boundary. But there is hope! Haydock and Nex have derived a minimally-reflecting boundary condition that has proved useful in discrete systems for constructing densities of states and other distributions from moments or continued fractions. Solutions satisfying this MBTS condition minimize reflections by maximally breaking time-reversal symmetry. The approach has now been extended to studies employing continuous spatial wave functions. Results for model systems and surfaces will be presented.