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 View the MathML source. We show the dependence of excitation energies on the strength of Coulomb interaction and the photoabsorption spectra.