Investigation of Ag2O Thermal Decomposition by Terahertz Time-Domain Spectroscopy

Application of terahertz time-domain spectroscopy is demonstrated to study the process of Ag2O thermal decomposition. In the process of decomposition, the time-resolved signals are characterized by broad oscillations and decreased intensity, and Tttz pulse essentially contains two broad spectral components： one centered at around 0.35 THz and a band with a maximum at around 0.81 THz shift to 0.71 THz. Optical absorption spectra of different specimens are studied in the frequency range 0.3-1.4 THz and the data are analyzed by the relevant theory of the effective medium approach combined with the Drude-Lorentz model. The analysis suggests that optical properties stem from the Drude term for the metallic phase and the Lorentz term for the insulator phase in the complex system.     

金属导线偶合THz表面等离子体波

利用THz时域光谱技术,研究了具有不同排列参数的金属导线阵列的透射特性,分析了金属导线半径,排列间隔以及入射电场的偏振方向对表面等离子体波产生和传播的影响.在具有等间隔缝隙的金属导线中,当电场偏振方向垂直金属导线时,透射信号受等离子模式和谐振腔模式的共振效应的影响;而当电场偏振平行金属导线时,只存在谐振腔模式的共振. 关键词： THz 时域光谱 铜导线 表面等离子体     

Excitonic level structures of LH1 and LH2 of purple photosynthetic bacteria using an analytical approach

The excitonic level structure of a ring-like chain of dimers is discussed analytically in order to aid the understanding of the possible spectral properties of LH1 and LH2 of purple photosynthetic bacteria. Under the approximation of dipole－dipole interaction between Bchls, the excitonic levels, bandwidths and energy gap between two Davydov subbands are expressed analytically in terms of interaction energies and configurational parameters of dipoles. Our model includes all the interactions between pigment molecules in the system. The oscillator strengths and circular dichroism (CD) for the excitonic states are also presented analytically. The simulated absorption and CD spectra of LH1 and LH2 complexes reproduce the main features of the measured results.     

基于自适应神经模糊推理系统的光谱预测

由于神经网络具有自适应以及自学习功能,模糊系统具有很好的非线性推理能力。将二者相结合的自适应神经模糊推理系统吸收了二者的优点,将其应用于对模型特征的分析和建模上,通过对数据的学习可以预测特性非常复杂的系统,如荧光光谱。荧光光谱分析法操作简单,精度高,分析速度快,是研究分子内部结构的重要手段。预测荧光光谱更具有重要意义。文章以N₂分子的脉冲放电的发射谱为例进行了预测,预测结果显示,该方法可以预测光谱谱线的重要信息,误差均小于1.66%,达到了此次实验的精度要求,具有满意的效果。对光谱的预测是切实可行的。