AM1/CI study of the first-order hyperpolarizability for push–pull quinones and push–pull polyenes A two-level model evaluation

Abstract

A set of quinone derivatives with different donor and acceptor groups is obtained. The first-order hyperpolarizabilities (β) are determined by using the two-level model at the level of AM1/CI. The transition moment (µ_ge), the dipole moment difference (Δµ) between the ground and excited states and the maximum absorption wavelength (λ_max) are calculated. The influence of the strength of the donor–acceptor pairs upon these crucial two-level parameters is investigated with respect to the electronic features. The relationship between these parameters and the first-order hyperpolarizability is discussed. For comparison, the results for push–pull hexatriene, another π-conjugated system, are also discussed.