Differences in Two-photon and One-photon Absorption Profiles induced by Vibronic Coupling. The case of dioxaborine heterocyclic dye.

A theoretical study of a dioxaborine heterocyclic compound in solution provides a case study for an analysis of the effects induced by the so-called Herzberg–Teller (HT) vibronic coupling on the one- (OPA) and two-photon absorption (TPA) spectra. For TPA, the HT vibronic coupling induces differences in the shapes of the absorption band. The study highlights the importance of vibronic coupling as a potentially important mechanism in absorption spectroscopy, able to explain differences in the OPA/TPA spectra.