势能面移动对三(2-苯基吡啶)合铱磷光光谱影响的理论研究

Theoretical study on the influence of the displacement of the potential energy surface on the phosphorescence spectrum of tris(2-phenylpyridine) iridium

采用密度泛函理论及赝势基组对三(2-苯基吡啶)合铱(Ir(ppy)3)的基态及三重态结构进行优化,并分析了这两个态各自的振动模式,在此基础上计算了电子从三重态跃迁回基态的势能面移动,得到了该过程的重整能.由于0→1跃迁对Ir(ppy)3的磷光光谱有重要影响,我们利用Frank-Condon因子与势能面移动的联系,在给定的半高宽下,计算并得到了Ir(ppy)3的磷光光谱,结果与实验吻合较好.

Using density functional theory （DFT） and employing pseudopotential basis sets Lanl2DZ, the geometries of ground and triplet states of tris（2-phenylpyridine） iridium （Ir（ppy）3） were optimized. The vibrational modes of both the states were computed based on the stable geometries and assigned, then the potential energy surface displacements between the triplet state and the ground state were calculated, furthermore the reorganization energy in the radiative transition process can be obtained by normal mode analysis and displacement of potential energy surface, which are very close to each other. Since 0→1 transition can significantly affect the Ir（ppy）3 phosphorescence spectrum, and Frank-Condon factors can be expressed by Huang-Rhys factor, we use the expression to model the phosphorescence spectrum of Ir（ppy）3 after the full width at half maximum was given, which showed good agreement with the experiment.