Theoretical study of the stability of X<sub><i>N</i></sub><sup><i>n</i></sup> (<i>n</i>=−1, 0, +1, +2; X=Ag, Cu;<i>N</i>≤25) clusters as a function of size using a non-local density functional formalism

Zeitschrift für Physik D 12, 209 - 211 (1989)

Theoretical study of the stability of XNn (n=−1, 0, +1, +2; X=Ag, Cu;N≤25) clusters as a function of size using a non-local density functional formalism

A. Rubio, L. C. Balbás, A. Vega

The spherical jellium model and self-consistent Weighted Density Approximation (WDA) to density functional theory have been used to study the stability of X Nn (n=–1, 0, +1, +2; X=Ag, Cu;Nle25) clusters. The calculated magic numbers coincide with the observed ones. The first (IP1) and second (IP2) ionization potentials of AgN and CuN as a function of size show the typical oscillations induced by the electronic shell-filling effect. IP1 of CuN is about 0.5 eV higher than IP1 of AgN in the range studied (Nle25). For both CuN and AgN, IP1 appears to converge well towards the respective experimental values of the work function. The use of WDA allows us to obtain bound negative clusters of small size or with a nearly empty external shell, which is not possible using the Local Density Approximation (LDA) [1, 2]. However the electron affinity of XN clusters obtained as the difference of energies of the neutral and the negatively charged clusters, becomes negative forN=2, 3 and 8 (very close to zero forN=8), revealing that WDA needs further refinements.

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http://dx.doi.org/10.1007/BF01426939