Quantum Chemical Calculations Of Third-Order Nonlinear Optical Properties For Organic Open-Shell Systems: Nitronyl Nitroxide Radicals And Several π-Conjugated Systems Having Unique Structures

摘要

The static second hyperpolarizability (γ) for several open-shell systems, which are predicted to exhibit a negative γ by our classification rule of γ based on symmetric resonance structures with invertible polarization (SRIP), has been studied. The remarkable electron correlation dependence has been observed in the magnitude and sign of γ. We also investigate the applicability of the density functional theory (DFT) methods for the γ values of these systems. By tuning the mixing parameter of DFT/HF exchange term, a DFT method can reproduce the γ values at the higher-order electron correlation method.