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本文从拉曼峰强出发, 求得了反-2, 3-环氧丁烷分子的拉曼键极化率, 明确了拉曼激发下电荷的分布的信息. 还从旋光拉曼(Raman optical activity, ROA)谱的峰强, 求取了该分子的旋光拉曼键极化率. 由分子手性中心的C-H产生的偶极矩与拉曼激发过程中, 电荷流动产生的跃迁磁偶极矩的耦合, 来理解旋光拉曼活性产生的机理. 分析表明, 旋光拉曼活性分子手性中心的C-H键两侧的旋光拉曼极化率符号相反, 显示着手性分子局域的不对称性. 还得到了对称和反对称坐标的键极化率和旋光拉曼极化率, 并且从对称性的角度, 即C2群的不可约表示, 讨论了这些极化率的内涵.In this article, Raman bond polarizability of trans-2,3-epoxybutane is derived from its Raman intensity, and the charge distribution of its Raman excited virtual state is obtained. The differential bond polarizability is also obtained from its Raman optical activity (ROA) intensity. The Raman chirality is explained via the coupling between the dipole moment induced by the C-H bond around the chiral center and the magnetic dipole moment which is caused by the electronic current generated in the Raman process. Further analysis shows that the differential bond polarizabilities on the two opposite sides of the C-H bond around the chiral center are of opposite sign. This demonstrates the local asymmetry of this chiral molecule. The symmetric and antisymmetric coordinates are also analyzed, and their results are explained via the irreducible representations of C2 group.
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Keywords:
- Raman optical activity (ROA) /
- Raman intensity /
- differential bond polarizability /
- Raman excited virtual state
[1] Barron L D, Buckingham A D 1971 Mol. Phys. 10 1111
[2] Barren L D, Bogaard M P, Buckingham A D 1973 J. Am. Chem. Soc. 95 603
[3] Polavarapu P L, Hecht L, Barron L D 1993 J. Phys. Chem. 97 1793
[4] Polavarapu P L 1997 Mol. Phys. 91 3551
[5] Wu G Z 2007 Raman Spectroscopy: A Intensity Approach (Beijing: Science Press) p70-84 (in Chinese) [吴国祯 2007 拉曼谱学-峰强中的信息 (北京: 科学出版社)第70—84页]
[6] Fang Y, Wu G Z, Wang P 2012 Chemical Physics 393 140
[7] Fang Y, Wu G Z, Wang P 2012 Spectrochimica Acta Part A 88 216
[8] Thomas M Black, Pranati K B 1990 J. Am. Chem. Soc. 112 1479
[9] Fang C, Wu G Z 2009 J. Raman Spectrosc. 40 308
[10] Fang C, Liu Z J, Wu G Z 2008 J. Mol. Struct. 885 168
[11] Fang C, Wu G Z 2007 J. Raman Spectrosc. 38 1416
[12] Shen H, Wu G Z, Wang P J, Chin. Phys. B (已接受)
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[1] Barron L D, Buckingham A D 1971 Mol. Phys. 10 1111
[2] Barren L D, Bogaard M P, Buckingham A D 1973 J. Am. Chem. Soc. 95 603
[3] Polavarapu P L, Hecht L, Barron L D 1993 J. Phys. Chem. 97 1793
[4] Polavarapu P L 1997 Mol. Phys. 91 3551
[5] Wu G Z 2007 Raman Spectroscopy: A Intensity Approach (Beijing: Science Press) p70-84 (in Chinese) [吴国祯 2007 拉曼谱学-峰强中的信息 (北京: 科学出版社)第70—84页]
[6] Fang Y, Wu G Z, Wang P 2012 Chemical Physics 393 140
[7] Fang Y, Wu G Z, Wang P 2012 Spectrochimica Acta Part A 88 216
[8] Thomas M Black, Pranati K B 1990 J. Am. Chem. Soc. 112 1479
[9] Fang C, Wu G Z 2009 J. Raman Spectrosc. 40 308
[10] Fang C, Liu Z J, Wu G Z 2008 J. Mol. Struct. 885 168
[11] Fang C, Wu G Z 2007 J. Raman Spectrosc. 38 1416
[12] Shen H, Wu G Z, Wang P J, Chin. Phys. B (已接受)
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