Optical response of bimetallic and doped alkali clusters

Computational Materials Science 2, 509 - 518 (1994)

Optical response of bimetallic and doped alkali clusters

L.C. Balbás, A. Rubio, M.B. Torres

We calculate the photoabsorption spectra of bimetallic LixNa20−x (0less-than-or-equals, slantxless-than-or-equals, slant20) and of doped Li9H and Na9X (X = F, Cl, Br, I) alkali clusters by means of the time dependent local density approximation. The ground state geometry and electronic structure are obtained by minimization of total energy from Kohn-Sham self-consistent calculations within the spherically averaged pseudopotential method. The results are discussed in relation to the ionic and electronic structures and composition of the clusters. For each cluster in the series LixNa20−x with a given content of lithium we obtain several ionic configurations with nearly the same total energy. These isomeric clusters yield however distinguishable photoabsorption spectra. For doped clusters we assume that the impurity atom is located at the center of the cluster and the alkali atoms form a spherical shell around, resulting photoabsorption spectra in qualitative agreement with available photodepletion experiments.

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