Ab initio studies of the lambda(max) of naphthoquinones dyes

Using a state-of-the-art time-dependent density functional (TD-DFT) approach that includes the explicit consideration of bulk medium effects on both the ground-state geometry and the electronic spectrum, we have determined the lambda(max) of 86 naphthoquinones (NQ) dyes in various solvents for a total of 151 cases. In most cases, TD-DFT provides the correct ordering of transitions for substituted NQ dyes. Comparisons with experimental values lead to a mean signed error of -7.2 nm (0.039 eV) and a mean absolute error of 20.1 nm (0.113 eV). It turns out that the average errors are smaller for the hydroxy and methoxy derivatives, than for amino substituted dyes. It is also demonstrated that the statistical treatment of the data does not significantly improve the agreement between the experimental and the theoretical values. We also discuss average basis set effects and solvatochromism.