温度对短链多烯生物分子β胡萝卜素拉曼光谱的影响

Effect of Temperature on the Raman Spectrum of Short-chain Polyenes Biological Molecules β-Carotene

用Gobin Yvon hr800拉曼光谱仪及与之相连接的Linkam,Thms600加热装置,测量了含9个C-C共轭双键的β胡萝卜素分子在二甲基亚砜中在25～73℃范围内的拉曼光谱.结果表明,短链多烯生物分子β胡萝卜素在液体中有很大的拉曼散射截面[6.5×10-23cm2/(molecule·Sr)],除共振效应外,β胡萝卜素分子结构有序产生较强的弱阻尼C-C键相干振动,是获得大拉曼散射截面的重要因素.温度对多烯类链状线性分子结构有序性影响很大.温度升高,分子结构有序性下降,C-C键弱阻尼相干振动减弱,C-C键长变短,各C-C键键长略有不同,使拉曼散射截面减少,拉曼光谱谱线蓝移,振动频率成分增加使线宽增加.

Raman spectra of β-carotene with 9 conjugated double bonds polyenes bioligical molecules were measured in dimethyl sulfoxide（ DMSO） solution,at temperature range from 298 K to 346 K（ 25—73 ℃） in this experiment by Gobin Yvon hr800 Raman spectrometer commreted Linkam,Thms600 heating device. The results show that short-chain polyenes biological molecules β-carotene have larger Raman scattering cross section[6. 5 × 10-23 cm2 /（ molecule·Sr） ]. Besides the Resonance Raman effect,the molecular structural order of β-carotene,which can generate coherent weak damping C-C bond vibration is an important factor,can lead to high Raman scattering cross section. The temperature has great effect on polyenic linear molecular structural order. Due to the temperature increases,the molecular structural order of β-carotene decreases,which lead to the weak of coherent weakly damping C-C bond vibration,the C-C bond length changes short. Because the C-C bond length is slightly different,the Raman scattering cross section decreases. And the frequency shifts towards higher frequencies,the frequency components of vibration increase,and the Raman linewidth becomes broadened.