Tight‐binding parameterization of transition and noble metal clusters

Abstract

AbstractThe possibility of a tight‐binding (TB) parameterization of transition metal (TM) and noble metal clusters is investigated. An original procedure is proposed that allows one to derive the values of orthogonal‐TB matrix elements reproducing the exact one‐electron spectrum from an analysis of first‐principles density functional calculations. The procedure is applied to selected small metals clusters: Ni2, Pt2, Au2, Pt3, Ni13, Pt13, and Au13. Ni, Pt, and Au are taken as examples of first‐row TM and third‐row transition and noble metals. The diatomic molecules are chosen as the simplest examples of TM clusters, Pt3 allows one to compare closed‐shell and spin‐symmetry‐broken configurations, and the 13‐atom clusters are representative of larger systems. With respect to the current TB parameterizations, it is found that the p‐orbitals lie at higher energies (especially for third‐row TMs) than usually assumed, the diagonal matrix elements among d‐functions also depend on the bond directionality, and an s‐orbital relaxation effect is present for third‐row elements (especially Pt). The validity of the TB approach is substantially confirmed, as well as the possibility of a TB treatment of transition and noble metal clusters, provided that these effects are taken into account (e.g., more than one s‐orbital should be included in the TB parameterization for platinum). © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004