利用Vaspec-2048-2紫外光谱仪和Renishaw InVia型共聚焦拉曼光谱仪,测量了极性溶剂1,2-二氯乙烷碘溶液中的β-胡萝卜素的紫外-可见吸收光谱和拉曼光谱.结果表明,生成络合物的β-胡萝卜素在460 nm处的紫外-可见吸收峰消失,并在1000 nm处出现β-胡萝卜素与碘形成络合物的吸收峰,致使514.5 nm激光激发时观察不到络合物中C-C(C—C,C=C)键的共振拉曼光谱.而溶液中没有形成络合物的β-胡萝卜素的C-C键拉曼散射截面减小.其机理为:β-胡萝卜素和碘溶液不稳定,β-胡萝卜素分子结构有序性减弱,导致相干弱阻尼C-C键振动减弱,使得其拉曼散射截面减小.
β-Carotene is the polyenes linear biological molecule,which can form charge transfer complex in iodine solution.We measured the UV-Vis absorption and Raman spectra by the Avaspec-2048-2 spectrophotometer and the micro Raman spectrometer(Renishaw InVia Raman microscope),respectively.The result show that the UV-Vis absorption spectra at 460 nm of β-carotene disappeare in polar solvent 1,2-dichloroe-thane.And a new,intense absorption band of complex which was formed by β-carotene and iodine was found at 1000 nm.So the resonance Raman spectra of β-carotene in complex couldn′t be observed by 514.5 nm Laser.And Raman cross section of β-caroten that wasn′t in the complex reduced.Due to the solution of β-carotene and iodine was unstable,the molecule structural order of β-caroten weaked,which lead to the weak of coherent weakly damped CC vibrations,and made the Raman scattering cross section reduced.