Quantum simulations in materials science: molecular monolayers and crystals

Low temperature properties and anomalies in crystals and molecular monolaye rs are studied by path integral Monte Carlo (PIMC) simulations. For light p articles (H-2, D-2) adsorbed on graphite anomalies in the transition to the low temperature root 3-phases have been observed in experiments and are an alyzed by PIMC. The computed thermal expansion of various crystalline mater ials (Si,N-2) is in much better agreement with experiments compared to the results obtained with purely classical simulations. (C) 1999 Elsevier Scien ce B.V. All rights reserved.