1. Simulator Development Department, KFKI Atomic Energy Research Institute, H-1525 Budapest, P. O. Box 49, Hungary
2. Materials Department, KFKI Atomic Energy Research Institute, H-1525 Budapest, P. O. Box 49, Hungary
3. Institut für Physikalische Chemie, Universität zu Köln, Luxemburger Str. 116, D-50939 Köln, Germany