Basis set and functional effects on excited‐state properties: Three bicyclic chromogens as working examples

We have computed, at the time‐department density functional theory, TD‐DFT level of approximation, the ground‐ and excited‐state properties of three typical chromophores, namely indole, coumarin, and benzofurazan, using six functionals (B3LYP, B3P86, PBE0, BMK, BH&HLYP, and CAM‐B3LYP) and four atomic basis sets (BSs), the larger being 6‐311++G(2d,2p). It turned out that diffuse functions are necessary to obtain correct vertical transition energies. The selected functional mainly impacts on these energies, but the differences of vibrational energies between the ground‐ and excited‐states are almost BS and functional independent. The adiabatic gap estimated with total energies or with Gibbs free enthalpies are nearly the same provided the ZPVE effects are accounted for. Int J Quantum Chem, 2012.