Poling behavior of nonlinear and linear optical properties in one- and two-dimensional charge-transfer molecules

Abstract

Evolutions of linear and nonlinear optical properties with poling electric field were studied for 3,6-dinitro-N-ethylcarbazole and 3-nitro-N-ethylcarbazole, respectively with two and one dimensional charge transfer character, were theoretically studied. Molecular geometries were fully optimized via Austin-Model 1 (AM1) Hartree-Fock semiempirical method. Intermediate Neglect of Differential Overlap (INDO) method with Single Configuration Interaction (SCI) was applied to the optimized geometries. Components of the molecular hyperpolarizability tensors were obtained by means of Sum Over State (SOS) method. Theoretical results reproduce the effect of poling upon the absorption spectra of these molecules which were experimentally observed. The result of the evolution of the second order nonlinear optical tensor components with poling factor shows larger off-diagonal components for the two dimensional charge transfer molecule.

ポーリング電場のもとでの線形・非線形光学的性質の変化を、それぞれ1次元および2次元の電荷移動特性をもつ3-ニトロ-N-エチルカルバゾールと3,6-ジニトロ-N-エチルカルバゾールについて理論的に研究した。分子のジオメトリーはAustin-Model1(AS1)の半経験的ハートリー・フォック法により十分に最適化した。この最適化したジオメトリーにINDO(Intermediate Neglect of Differential Overlap)SCI(Single Configuration Interaction)法を適用した。分子超分極率テンソルの成分はSOS(Sum Over State)法により求めた。得られた結果は、実験的に観測したこれらの分子の吸収スペクトルへのポーリングの効果を再現している。2次非線形光学テンソル成分のポーリング因子に対する変化の計算結果は、非対角成分が2次元電荷移動分子について比較的大きくなることを示した。