有序分子系统的线性与非线性光谱学的简化描述

通过对有序分子系统的线性与非线性光谱学的简化描述 ,帮助对有序分子体系光谱学进行研究的实验学家建立明确的物理图像和定量的研究工具 .这一描述是从最近对二阶非线性光学界面研究技术 ,即光学二次谐波 (SHG)和和频偏振振动光谱 (SFG VPS)的定量取向和偏振处理中推广出来的 .这一处理的方法关键在于简化线性和非线性光学中的有效极化率 ,构造出一个通用的取向泛函 ,并能通过实验参数清晰地计算出取向泛函的取向和强度因子 .同时还讨论了相干光谱技术在准确测量有序分子体系的取向和序的相比于非相干光谱方法的优点 .

A Simplified Formulation of Linear and Nonlinear Spectroscopy of Ordered Molecular Systems

A simplified formulation for treating the linear and nonlinear spectroscopy of ordered molecular systems is presented, in order to help experimentalists to have an explicit physical picture and quantitative tool on using linear and nonlinear spectroscopy to study molecules in ordered molecular systems. This formulation is expended from our recent quantitative orientational and polarization treatment on second-order nonlinear spectroscopic techniques in interface studies, namely, the Second Harmonic Generation (SHG) and Sum Frequency Generation- Vibrational Polarization Spectroscopy (SFG-VPS). The key to this formulation is to simplify the effective linear or nonlinear molecular susceptibility and construct the general orientational functional with a clear approach to calculate the orientational and intensity parameters from the experimental parameters, which determines the orientational and polarization behavior of the general orientational functional in a particular experimental configuration. Also discussed are the advantages of coherent spectroscopic techniques over incoherent ones for the accurate measurement of orientation and ordering of ordered molecular system.