14族杂环戊二烯分子(硅、锗、锡)的电子结构与光谱性质(英文)

Electronic Structures and Spectroscopic Properties of Group-14 Metalloles MPh_6 (M=Si,Ge,Sn)

14族杂原子取代的杂环戊二烯分子具有独特的光谱性质,成为发光材料的明星分子.为了更深层次地理解硅、锗、锡杂环戊二烯分子的光谱性质,本文从理论上计算了它们的电子结构及其吸收和发射光谱.分别采用密度泛函理论(DFT)和含时密度泛函理论(TD-DFT),优化了硅、锗、锡杂环戊二烯分子基态和第一激发态的平衡构型,计算了电子结构和振动性质.在此基础上,运用振动关联函数公式计算了吸收光谱和发射光谱.得到的吸收光谱和发射光谱,特别是发射光谱的半峰宽与现有的实验值吻合很好.通过分析结构和光谱性质的关系,指出光谱的性质主要取决于苯环转动对应的低频振动模式和中心环C—C键的伸缩振动对应的高频振动模式.

Group-14 metalloles possess interesting optical properties and are promising molecules for light-emitting materials.We present a theoretical study of the electronic structures and the optical spectra from silole to stannole to gain insight into their optical properties.The optimized equilibrium geometries and the electronic and vibrational structures for the ground state （S0） and the first singlet excited state （S1） were calculated using density functional theory （DFT） and time-dependent density functional theory （TD-DFT）,respectively.The optical absorption and emission spectra were calculated using the thermal vibration correlation function formalism.The lineshapes of the calculated optical absorption and emission spectra,especially the full width at half maximum for all the compounds at room temperature,were found to be in good agreement with the available experimental data.Low-frequency modes that are assigned to the rotation motion of free aromatic rings and the high-frequency modes related to the stretching vibration of carboncarbon bonds contribute greatly to the optical features such as the bandwidth of the optical line-shapes.