A reliable method for fitting TD-DFT transitions to experimental UV-visible spectra

A nonlinear-least-squares algorithm was implemented in the context of iterative fitting of UV-visible spectra. This model mixes energetic transition data computed by a TD-DFT approach, using exchange and correlation hybrid functionals, with parameters determined by curve fitting. UV-visible spectra are modeled as a sum of gaussian function with a full width at half maximum (FWHM) fitted for each electronic transition. This model mixing theoretical and experimental data, is able to reproduce experiments with a faithful similarity.