LENS-European Laboratory for Non-Linear Spectroscopy, Università di Firenze, via N. Carrara 1, 50019 Sesto F.no (FI), Italy.
J Chem Phys. 2012 Dec 14;137(22):224506. doi: 10.1063/1.4770265.
The optical properties of picene at ambient conditions have been investigated through the measurement of UV/Vis absorption and fluorescence spectra and of excitation profiles, using one- and two-photon excitation, in solution and in the crystal phase. For solvated picene an assignment of the vibronic structure of the transitions to the four lowest-energy excited singlet states (S(1)-S(4)) has been obtained from the absorption data, and the vibronic structure of the fluorescence spectra has been assigned. The absorption and fluorescence spectra of the solid phase can be interpreted according to the single molecule analysis. Nevertheless, the strong increase of the optical density in the spectral region of the lowest HOMO-LUMO transitions and the frequency shift of absorption and fluorescence bands may be explained by a mixing of the states of adjacent molecules in the crystal. Moreover, peculiar emission features depending on the crystal dimensions (10(-1) to 10(2) μm) are observed.
在环境条件下，通过测量紫外/可见吸收和荧光光谱以及使用单光子和双光子激发的激发轮廓，研究了并五苯的光学性质，分别在溶液和晶体相中进行。对于溶剂化的并五苯，通过吸收数据获得了跃迁到四个最低能量激发单线态（S(1)-S(4)）的振子结构的归属，并对荧光光谱的振子结构进行了归属。根据单分子分析，可以解释固态的吸收和荧光光谱。然而，在最低 HOMO-LUMO 跃迁的光谱区域中光学密度的强烈增加以及吸收和荧光带的频率位移可能是由晶体中相邻分子的状态混合引起的。此外，还观察到取决于晶体尺寸（10(-1) 至 10(2) μm）的特殊发射特征。
