A TD-DFT study of the absorption spectra of fast dye salts

The UV/visible spectra of a series of diazonium (N2+) fast dyes have been evaluated by using a time-dependent density functional theory approach explicitly taking into account bulk solvation effects. Using the PBE0 functional with the 6-311G(2d,2p) atomic basis set, the agreement between theory and experiment is excellent for these cationic species. The effects on the spectra of chemical substitution are analysed.