Effects of the structural order of canthaxanthin on the Raman scattering cross section in various solvents:A study by Raman spectroscopy and ab initio calculation  

作　　者：吴楠楠 里佐威 刘靖尧 欧阳顺利 

机构地区：[1]Key Laboratory of Integrated Exploitation of Bayan Obo Multi-Metal Resources,Inner Mongolia University of Science&Technology [2]College of Physics,Jilin University [3]Institute of Theoretical Chemistry,State Key Laboratory of Theoretical and Computational Chemistry,Jilin University

出　　处：《Chinese Physics B》2012年第10期195-200,共6页中国物理B（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (Grant Nos. 11004252 and 10974067);the National Basic Research Program of China (Grant No. 2012CB722802)

摘　　要：In this work,we measure the Raman scattering cross sections（RSCSs） of the carbon-carbon（CC） stretching vibrational modes of canthaxanthin in benzene,acetone,n-heptane,cyclohexane,and m-xylene.It is found that the absolute RSCS of CC stretching mode of canthaxanthin reaches a value of 10 24 cm ^-2 ·molecule ^-1 ·sr ^-1 at 8×10 ^-5 M,which is 6 orders of magnitude larger than general RSCS（10 30 cm 2 ·molecule 1 ·sr 1）,and the RSCSs of canthaxanthin in various solvents are very different due to the hydrogen bond.A theoretical interpretation of the magnetic experimental results is given,which is introduced in a qualitative nonlinear model of coherent weakly damped electron-lattice vibration in the structural order of polyene chains.In addition,the optimal structure and the bond length alternation（BLA） parameter of canthaxanthin are calculated using quantum chemistry calculation（at the b3lyp/6-31g（d,p） level of theory）.The theoretical calculations are in good agreement with the experimental results.Furthermore,the combination of Raman spectroscopy and the quantum chemistry calculation study would be a quite suitable method of studying the structures and the properties of the π-conjugated systems.In this work,we measure the Raman scattering cross sections（RSCSs） of the carbon-carbon（CC） stretching vibrational modes of canthaxanthin in benzene,acetone,n-heptane,cyclohexane,and m-xylene.It is found that the absolute RSCS of CC stretching mode of canthaxanthin reaches a value of 10 24 cm ^-2 ·molecule ^-1 ·sr ^-1 at 8×10 ^-5 M,which is 6 orders of magnitude larger than general RSCS（10 30 cm 2 ·molecule 1 ·sr 1）,and the RSCSs of canthaxanthin in various solvents are very different due to the hydrogen bond.A theoretical interpretation of the magnetic experimental results is given,which is introduced in a qualitative nonlinear model of coherent weakly damped electron-lattice vibration in the structural order of polyene chains.In addition,the optimal structure and the bond length alternation（BLA） parameter of canthaxanthin are calculated using quantum chemistry calculation（at the b3lyp/6-31g（d,p） level of theory）.The theoretical calculations are in good agreement with the experimental results.Furthermore,the combination of Raman spectroscopy and the quantum chemistry calculation study would be a quite suitable method of studying the structures and the properties of the π-conjugated systems.

关 键 词：Raman spectroscopy the bond length alternation（BLA） parameter quantum chemistry calculation CANTHAXANTHIN 

分 类 号：O561.3[理学—原子与分子物理]