文档介绍：2017-1-22 1激光拉曼光谱激光拉曼光谱陈建中山大学测试中心广东省显示材料与技术重点实验室 2017-1-22 2 Remote Raman Analysis on ary Missions ? To allow Raman spectroscopy at range of 10's of meters. ? This NASA-funded project is aimed at Mars landers or landers on other s, but also has terrestrial uses. 2017-1-22 3 分子中基团的振动和转动能级跃迁产生: 振-转光谱 2017-1-22 4 激光拉曼光谱基本原理 Rayleigh 散射: 弹性碰撞; 无能量交换,仅改变方向; Raman 散射: 非弹性碰撞;方向改变且有能量交换; Rayleigh 散射 Raman 散射 E 0基态, E 1振动激发态; E 0 + h? 0 ,E 1 + h? 0 激发虚态; 获得能量后,跃迁到激发虚态.(1928 年印度物理学家 Raman C V 发现; 1960 年快速发展) h ?? E 0E 1V =1 V =0 h? 0h? 0h? 0h? 0 + ?? E 1 + h ? 0E 0 + h ? 0h(? 0 - ??) 激发虚态 2017-1-22 5 基本原理 1. Raman 散射 Raman 散射的两种跃迁能量差: ? E=h (? 0 - ??) 产生 stokes 线;强;基态分子多; ? E=h (? 0 + ??) 产生反 stokes 线; 弱; Raman 位移: Raman 散射光与入射光频率差??; ANTI-STOKES ? 0 - ?? Rayleigh STOKES ? 0 + ??? 0 h(? 0 + ??) E 0E 1V =1 V =0 E 1 + h ? 0E 2 + h ? 0h ?? h? 0h(? 0 - ??) 2017-1-22 6 Rayleigh / Raman Transitions IR Absorptions 2017-1-22 7 Rayleigh / Raman Transitions and Spectra 2017-1-22 8 Rayleigh / Raman Transitions and Spectra 2017-1-22 9 The Spectrum plete Raman spectrum consists of: ? a Rayleigh scattered peak (high intensity, same wavelength as excitation) ? a series of Stokes-shifted peaks (low intensity, longer wavelength) ? a series of anti-Stokes shifted peaks (still lower intensity, shorter wavelength) ? spectrum independent of excitation wavelength (488, , or 1064 nm) Spectrum l 4 , using an Ar + laser at 488 nm. 2017-1-22 10 光散射的方法原理样品池透过光λ不变瑞利散射λ不变拉曼散射λ变λ增大λ减小