Место издания:Евразийский Национальный Университет им. Л.Н. Гумилёва, Астана, Казахстан
Первая страница:27
Последняя страница:27
Аннотация:Mixed AuPd and AuNi clusters are optimized for the various accessible spin multiplicities (SM). For pure gold clusters only singlet and doublet SM for even or odd number of electrons are considered. It is obtained that in AunNi clusters the average interatomic distances increase. The maximum value of Me-Me bond length changing is 0,024 A for Au4Ni cluster. The calculated bond energies per atom increase when the numbers of atoms in clusters increase. It has been shown, that in AuPd bclusters the charge in Pd atom oscillates depending on composition of a cluster, while most gold atoms are negativily charged. Some discrepancies are between Mulliken and NPA schemes of calculation, and Hirshfeld, where Pd possesses different charge. In order to clarify the nature of M-Au binding in clusters the visualization of HOMO is carried out. Highest occupied molecular orbilas up to HOMO-2 in Au6Pd are formed through the overlap of Au and Pd d-orbitals, representing the bonds between these atoms in the cluster. At the same time the HOMO in Au6Ni reflect the position of three different lone pairs on the Ni atom, while the bonding orbitals have lower energy, indicating the higher stability of this cluster. This fact is confirmed by calculation of binding energies and reflects the tendency which is common for all bimitallic AunX clusters.