ACCURATE AB-INITIO ENERGETICS OF EXTENDED SYSTEMS VIA EXPLICIT CORRELATION EMBEDDED IN A DENSITY-FUNCTIONAL ENVIRONMENT

We present a new embedding technique that combines density functional theory (DFT) and explicit electron-correlation techniques. We construc t a periodic-DFT-based embedding potential as a local one-electron ope rator within more accurate electron-correlation calculations. We demon strate how DFT calculations can be systematically improved via this pr ocedure. We benchmark the method against nearly exact calculations wit h a simple model of Li2Mg2 and further corroborate it with an applicat ion to the experimentally well studied CO/Cu(111) system. Our results are in good agreement with near-full configuration interaction (CI) ca lculations in the former case and experimental adsorbate binding energ ies in the latter. (C) 1998 Published by Elsevier Science B.V. All rig hts reserved.