Time-dependent density functional theory of excitation energies of closed-shell quantum dots

We study the low-energy excitations of two-dimensional elliptical quantum dots with closed-shell structures using time-dependent density functional theory (TDDFT). We find that TDDFT gives fairly accurate results for the low-energy excitations and describes the spin singlet-triplet transition due to the exchange energy. The deviations from exact-diagonalization results are less than 0.20 meV. We show the dependence of excitation energies on the strength of Coulomb interaction and the photoabsorption spectra. (C) 2003 Elsevier B.V. All rights reserved.