一组线性稠环芳香烃的等离激元激发
Plasmon Excitation in a Set of Linear Polycyclic Aromatic Hydrocarbons

采用含时密度泛函理论,研究了一组线性稠环芳香烃量子点的等离激元激发.沿着线性稠环芳香烃所在的平面方向,体系中有两个主要的等离激元共振带：一个位于3.9eV附近；另一个位于16eV附近.随着线性稠环芳香烃长度的增加,在低能共振区,沿不同方向激发时,体系的吸收峰分别发生了蓝移和红移.此外,与并五苯相比,在低能共振区,一氯并五苯的吸收光谱的吸收峰发生了红移和展宽,其中氯原子位于并五苯的两端时对一氯并五苯等离激元激发影响较大.在低能共振区,线性稠环芳香烃的等离激元共振模式与石墨烯量子点相似.
Time-dependent density functional theory has been used to investigate the plasmon excitation processes in a set of linear polycyclic aromatic hydrocarbons. Along the direction parallel to the linear polycyclic aromatic plane, there are two main plasmon bands, one around 3.9 eV and the other around 16 eV. In the low-energy resonance region, with the increase of the side length of the linear polycyclic aromatic hydrocarbons, the absorption peaks of the system are respectively blue-shifted and red-shifted along different excitation directions. Moreover, in the low-energy resonance region, compared with the pentacene, the photo absorption strength line of a chlorinated pentacene are red-shifted and greatly broadens.When the chlorine atoms at the both end of the pentacene, it make greatly influence to plasmon excitation of a chlorinated pentacene. In the low-energy resonance region, plasmon excitation in linear polycyclic aromatic hydrocarbons is similar to grapheme quantum dot.