Predictive TDDFT Methodology for Aromatic Molecules UV-Vis properties: from Benchmark to Applications

The absorption and emission properties of a series of 44 aromatic molecules have been investigated in Time Dependent Density Functional Theory (TDDFT) using different exchange-correlation functionals. Solvent effects have been included within linear response (LR) and state specific (SS) polarisable continuum model (PCM). The comparison with experimental UV-Vis data showed reasonable agreement for all the aromatic molecules when & omega;B97XD with SS-PCM is used. In particular, we found an accurate linear correlation between experimental and theoretical results which is revealed in an equation for absorption and another equation for emission derived from a linear fitting between theoretical and experimental data. Through these linear equations we propose a simple, pragmatic and effective approach able to describe and predict the absorption and the emission of aromatic molecules with a reasonable computational cost.