Effects of molecular dynamics and solvation on the electronic structure of molecular probes

Most spectroscopic parameters are influenced by nuclear dynamics and by the chem. environment. However, proper inclusion of these effects still represents a challenge in computational spectroscopy studies. In many cases, a route coupling satisfactory accuracy with reasonable computational costs consists in the integration of DFT-based methods to compute spectroscopic parameters, with ab initio mol. dynamics simulations to sample from the classical phase space of the system. Here, we discuss the application of this approach in two case studies of remarkable practical interest, namely the simulation of the absorption spectrum of 9-methyladenine, an adenine nucleoside model; and the prediction of ESR parameters for nitroxyl radicals, the prototypical spin probes. In both cases, the accuracy of the results increases significantly when the subtle interplay of intra-mol. dynamics and solvent effects is introduced.