Two-Photon Absorption and Second Hyperpolarizability of the Linear Quadrupolar Molecule

摘要: The two-photon absorption (TPA) cross section and the second hyperpolarizability (γ) of linear quadrupolar molecule are theoretically investigated by using ab initio calculation methods for a few series molecules. relationships between molecular structure TPA as well NLO property established. It is found that, strengths donors acceptors increase, (i) both energy gap first excited electronic state, |e>, ground |g>, that TPA-allowed state |f> |g> decrease, (ii) difference, |Efe − Eeg|, which detuning factor affecting matrix element, decreases, (iii) product transition dipole elements, | |, associated with increases. These effects combined to make monotonically increase donor acceptor increase. hyperpolarizabilities same ...