Kytka M, Gisslen L, Gerlach A, Heinemeyer U, Kovác J, Scholz R, Schreiber F
Institut fur Angewandte Physik, Universität Tübingen, Germany.
J Chem Phys. 2009 Jun 7;130(21):214507. doi: 10.1063/1.3147009.
In order to investigate the optical properties of rubrene we study the vibronic progression of the first absorption band (lowest pi-->pi( *) transition). We analyze the dielectric function epsilon(2) of rubrene in solution and thin films using the displaced harmonic oscillator model and derive all relevant parameters of the vibronic progression. The findings are supplemented by density functional calculations using B3LYP hybrid functionals. Our theoretical results for the molecule in two different conformations, i.e., with a twisted or planar tetracene backbone, are in very good agreement with the experimental data obtained for rubrene in solution and thin films. Moreover, a simulation based on the monomer spectrum and the calculated transition energies of the two conformations indicates that the thin film spectrum of rubrene is dominated by the twisted isomer.
为了研究红荧烯的光学性质，我们研究了第一吸收带（最低的π→π*跃迁）的振动电子谱带序列。我们使用位移谐振子模型分析了红荧烯在溶液和薄膜中的介电函数ε(2)，并推导了振动电子谱带序列的所有相关参数。研究结果通过使用B3LYP杂化泛函的密度泛函计算得到补充。我们对处于两种不同构象（即具有扭曲或平面并四苯主链）的分子的理论结果，与在溶液和薄膜中获得的红荧烯实验数据非常吻合。此外，基于单体光谱和两种构象的计算跃迁能的模拟表明，红荧烯的薄膜光谱主要由扭曲异构体主导。
