8-羟基喹啉铍及其衍生物电子光谱性质的含时密度泛函理论研究

TD-DFT Study on Electronic Spectrum Property for Bis(8-hydroxyquinoline) Beryllium and Its Derivatives

运用密度泛函理论 (DFT) B3 LYP方法和 ab initio HF单激发组态相互作用 (CIS)法分别优化了有机金属配合物 8-羟基喹啉铍 (Be Q2 )及其 3种衍生物分子的基态及最低激发单重态几何结构 .系统分析了分子结构、前线分子轨道特征和能级分布规律以探索电子跃迁机理 .应用含时密度泛函理论 (TD-DFT)计算分子的电子光谱 ,揭示了 Be Q2 及其衍生物的发光源于配体中 π→ π*电子跃迁 ,指出通过配体修饰可以有效地影响配合物前线分子轨道分布 ,调整发光波段 。

The molecular structures of the ground state and the first singlet excited state for organometalic complexes bis(8-hydroxyquinoline) beryllium (BeQ_2) and its three derivatives were optimized with the DFT B3LYP method and ab initio 'configuration interaction with single excitations'(CIS) method respectively. The frontier molecular orbital characteristics and energy levels of BeQ_2 have been analyzed systematically in order to study the electronic transition mechanism. Electronic spectrum property of complexes have been investigated with time-dependent density functional theory(TD-DFT), which indicates that the emissions of BeQ_2 and its derivatives originate from the electronic π→π * transitions within ligands. These theoretical results suggest that it might be possible to tune the emission wavelengths and improve charge transfer properties through the effect of ligand substituent on the distribution of frontier molecular orbital.