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TT: Fachverband Tiefe Temperaturen

TT 29: Correlated Electrons: Low-dimensional Systems - Materials 2

TT 29.12: Vortrag

Mittwoch, 25. März 2009, 17:15–17:30, HSZ 301

End states and singlet-triplet degeneracy in linear atomic chains — Antonio Monari¹, Valentina Vetere², Gian Luigi Bandazzoli¹, Stefano Evangelisti², and •Beate Paulus³ — ¹Dipartimento di Chimica Fisica e Inorganica, Universita di Bologna, Bologna, Italy — ²Laboratoire de Chimie et Physique Quantiques, Universite de Toulouse et CNRS, Toulouse Cedex, France — ³Institut für Chemie und Biochemie, Frei Universität Berlin, 14195 Berlin

The electronic structure of linear beryllium chains has been theoretically studied by using ab initio methods. It turns out that, for internuclear distances close to the equilibrium structure, two partially filled edge orbitals (’edge states’) localize at the chain ends. This gives rise to two low-lying states, a singlet ground state, ¹Σ_g and a quasi-degenerate triplet, ³Σ_u. the energy splitting goes rapidly to zero as the number of atoms in the chain is increased. Preliminary investigations indicate that this could be a general behavior shard by metals belonging to the groups 2 and 12.