First-Principles Calculation of Photoabsorption Spectra of Cadmium Selenide Clusters

Abstract

Photoabsorption spectra of magic-number cluster, (CdSe)₃₄, in a pearl-necklace geometry are calculated for the first time by a first-principles approach based on the density functional theory. Photoabsorption spectra for the (CdSe)₃₄ isolated-cage geometry is also calculated. We confirmed the size dependence by comparing them with our former result of smaller magic-number cluster, (CdSe)₁₃. Three different types of supercells are supposed to simulate the pearl-necklace geometry and a double-peak structure is found in a particular supercell. We found that the cluster geometry in this supercell is the most stable among the three.