β Scribed by Brynmor Mile; Philip D. Sillman
No coin nor oath required. For personal study only.
The application of electron paramagnetic resonance (EPR) spectroscopy in determining the geometric and electronic structures of small naked clusters, M~n~, of the alkali and coinage metals (n < 9) is assessed. The EPR spectra and the paramagnetic parameters derived therefrom provide stringent tests of quantitative molecular orbital calculations. Perturbations of the cluster shape by interaction with substrate molecules are readily detected and have a bearing on the dynamic nature of the active sites of heterogeneous catalysts. Previous studies of the metal trimers in hydrocarbon matrices are extended to the preparation of an unusual acute Na~3~ cluster associated with water and the heteronuclear clusters Na~2~Li and Au~2~Ag. Both adopt static obtuse ^2^B~2~ geometries and show no fluxionality, in contrast to the homonuclear pseudoβrotating JahnβTeller clusters Li~3~ and Na~3~. There is a reversal in paramagnetic parameters in the series Cu~3~, Ag~3~, Au~3~ which is due in part to the emergence of relativistic effects because of the high charge on the gold nucleus. The first ENDOR spectrum is reported of a metal cluster Li~3~, the parameters fitting exactly those determined from the more complex EPR spectrum of Li~3~. A new heteronuclear septameric species, Na~2~K~5~, has been examined which has the pentagonal bipyramidal structure seen for homonuclear septamer clusters. There is an unpaired spin density of 0.41 on the apical sodium nuclei with only 0.004 at the basal potassium nuclei.
π SIMILAR VOLUMES
Electronic structure, geometries, and magnetic moments of small Ni n (n = 2-6, 8, 13) clusters have been studied using a linear combination of atomic orbital-molecular orbital approach within the density functional formalism. The clusters are found to exhibit an abundance of electronic states corres