钕的电子拉曼光谱和一种新的拉曼增强机理  

Electronic Raman Bands of Neodymium and a New Mechanism for Raman Enhancement

作　　者：徐怡庄[1,2] 吴瑾光[1] 孙文秀[1] 陶栋梁[1] 宋增福[3] 翁诗甫[1] 许振华[1] 徐端夫[2] 徐光宪[1] 

机构地区：[1]北京大学化学与分子工程学院,稀土材料化学及应用国家重点实验室,北京100871 [2]中国科学院化学研究所,北京100871 [3]北京大学物理系,北京100080

出　　处：《高等学校化学学报》2003年第2期335-336,共2页Chemical Journal of Chinese Universities

基　　金：国家重点基础研究发展规划项目 (批准号 :G19980 6 130 7);国家自然科学基金 (批准号 :5 0 2 0 30 0 1;2 990 10 0 2 ;2 96 710 0 2 ;39730 16 0 ;2 0 0 2 30 0 5 ;5 97330 6 0 ;5 98730 30 ;5 995 30 0 1;5 990 30 0 8);中国科学院知识创新工程 (批准号:KJCX1-Y-0 3)

摘　　要：Strong electronic Raman bands corresponding to the transition between 4I 9/2 and 4I 11/2 manifolds of Nd 3+ are observed in the FT-Raman spectrum of neodymium complex because of the Raman enhancement effect. Neither resonant enhancement nor surface enhancement accounts for the Raman enhancement observed here. We propose a new mechanism of Raman enhancement(Feed-bach Raman Enhancement): the YAG laser excites the final state of Raman transition ( 4I 11/2 of Nd 3+) to the 4F 3/2 state and causes a significant decrease of the population of Nd 3+ at the 4I 11/2 state. This renders the population ratio of Nd 3+ at 4I 9/2 and 4I 11/2 deviates from the value required by the Boltzmann′s law. To restore equilibrium, Raman scattering is enhanced so that more Nd 3+ ions are brought from 4I 9/2 to 4I 11/2. This hypothesis gets support from the temperature-variable FT-Raman spectroscopic results. Additionally, obvious differences between Stokes and Anti-stokes Raman spectrum of Nd 3+ support our mechanismStrong electronic Raman bands corresponding to the transition between 4I 9/2 and 4I 11/2 manifolds of Nd 3+ are observed in the FT-Raman spectrum of neodymium complex because of the Raman enhancement effect. Neither resonant enhancement nor surface enhancement accounts for the Raman enhancement observed here. We propose a new mechanism of Raman enhancement(Feed-bach Raman Enhancement): the YAG laser excites the final state of Raman transition ( 4I 11/2 of Nd 3+) to the 4F 3/2 state and causes a significant decrease of the population of Nd 3+ at the 4I 11/2 state. This renders the population ratio of Nd 3+ at 4I 9/2 and 4I 11/2 deviates from the value required by the Boltzmann′s law. To restore equilibrium, Raman scattering is enhanced so that more Nd 3+ ions are brought from 4I 9/2 to 4I 11/2. This hypothesis gets support from the temperature-variable FT-Raman spectroscopic results. Additionally, obvious differences between Stokes and Anti-stokes Raman spectrum of Nd 3+ support our mechanism too

关 键 词：电子拉曼光谱 拉曼增强机理 钕 反馈 稀土 

分 类 号：O614.335[理学—无机化学] O657.37[理学—化学]