Structure and properties of molecular solutes in electronic excited states: a Polarizable Continuum Model approach based on the time-dependent density functional theory

This chapter reviews the methodological progress of the Polarizable Continuum Model (PCM) within the time-dependent Density Functonal Theory (TDDFT) to study chromophores in homogeneous solutions. The progress is represented by (i) a theory for the analytical gradients of the PCM-TDDFT excitation energies, which allows to determine the excited state geometries and first order properties within a relaxed density formalism; (ii) a state-specific version of the PCM-TDDFT to describe solute-solvent interaction in the excited states based on the changes of the electronic density; (iii) a time dependent version of the PCM-TDDFT able to describe the dynamical relaxation of the solvent after a vertical electronic transition in the solute. All these methodological advances are illustated and discussed with the help of numerical applications