Transition of the electronic response from molecular-like to jellium-like in cold, small sodium clusters

Autor: Martin Schmidt, Thomas Reiners, Hellmut Haberland, Christoph Ellert
Rok vydání: 1997
Předmět:
Zdroj: Zeitschrift f�r Physik D Atoms, Molecules and Clusters. 39:317-323
ISSN: 1431-5866
0178-7683
DOI: 10.1007/s004600050142
Popis: Absolute photoabsorption cross sections for Nan+ (2≤n≤21) were measured in the visible energy range. The cluster ions were produced in a gas aggregation source and thus have a canonical distribution of internal energy corresponding to a temperature of ∼ 105 K. The spectra for n≤9 and 11 exhibit between two and six absorption lines, and are in qualitative agreement with ab inito quantum chemical calculations. For n=15 and 21, the position of the resonances can be explained as excitations of a nearly free electron gas in a spheroidal container. An evolution is thus observed from molecular-like transitions to a giant collective resonance of the electron cloud. The integrated oscillator strength is 0.95 per 3s-electron in the energy range covered for n≥4, showing that the main excitations of the valence electrons have been found.
Databáze: OpenAIRE
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