The influence of geometry relaxation in solution on the first hyperpolarizability of mesoionic compounds

Abstract Theoretical results for the linear and nonlinear properties of mesoionic compounds in solution are presented. The electronic properties in solvents were determined by carrying out Sequential QM/MM calculations by means of the average solvent electrostatic configuration (ASEC) and the Free Energy Gradient (FEG) methods. The results illustrate the role played by geometry relaxation in the electronic properties of mesoionic rings in environments. It is found that environment-induced geometric changes impact on the molecular electronic structure of the mesoionic ring. MP2/aug-ccpVDZ results for the first hyperpolarizability obtained in solution are substantially smaller than the gas phase results.