Application of Time-Dependent Density-Functional Theory to C₆

We employ a real-space pseudopotential method to determine the ground state structure of the carbon cluster C₆ via simulated annealing and the corresponding optical absorption spectra from the adiabatic time-dependent density-functional theory (TDDFT) and the local density approximation (TDLDA). It is found that the ground state structure of the carbon cluster C₆ belongs to a monocyclic D_3h structure and the calculated spectra exhibit a variety of features that can be used for comparison against future experimental investigations.