Theoretical modeling of spectroscopic properties of molecules in solution: toward an effective dynamical discrete/continuum approach

In this work, we present an effective and flexible computational approach, which is the result of an on-going development conducted in our group, for simulating complex solute-solvent systems and computing relevant spectroscopic observables. Such an approach is based on QM/MM molecular dynamics techniques using non-periodic conductor boundary conditions and localized basis sets, combined with a posteriori high-level quantum mechanical methods for the calculation of spectroscopic parameters. As illustrative applications, we report structural and spectroscopic analyses of acetone, acrolein and glycine radical in aqueous solutions, where solvent effects on the NMR chemical shifts, UV absorption spectrum and EPR hyperfine coupling constants, respectively, are investigated and favorably compared to experimental measurements. In particular, it will be shown the importance of including dynamical effects in order to reproduce experimental data accurately. Moreover, we present an infrared analysis of formamide in both gas phase and acetonitrile from first-principle molecular dynamics simulations.