Light and nucleobases: A good interaction for everybody

This manuscript is based on the Invited Lecture Light and Nucleobases: a Good Interaction for Everybody (ICL-2017: 18th International Conference on Luminescence), focusing on applications of computational quantum chemistry to understand the photochemistry of fluorescent and nonfluorescent nucleobases. We begin with a summary on how UV radiation was a key player during selection of photostable (nonfluorescent) species as building blocks of our genetic material. Next, the need for developing fluorescent probes that can aid the use fluorescence spectroscopy is shown. The requirements of quantum chemical methods for properly describing the photochemical mechanisms are summarized, emphasizing the CASPT2 method. Two examples are used to illustrate the difference between the photochemical mechanisms behind nonfluorescent and fluorescent molecules. Finally, preliminary results on photochemical mechanisms of a new class of high emissive synthetic nucleobases is presented.