分子环境变化对振动退相时间影响的实验研究

Experimental study on vibration dephasing time varying with molecular surroundings

物质分子振动退相时间测量是一种非标记无损分子检测方法,用超连续谱时间分辨相干反斯托克斯拉曼散射方法可同时获得分子振动谱和退相时间.实验以苯甲腈和甲醇为样品,研究当分子环境变化时,其主要振动谱的振动退相时间变化情况.将苯甲腈与无水乙醇混合,测量了苯甲腈分子1017,2247和3085 cm-1三个典型分子振动的退相时间随环境变化的规律,并得到了变化后的振动退相时间.测量了甲醇分子2851,2960 cm-1两个相邻分子振动的退相时间随环境的变化情况,给出实验变化规律.这种方法具有检测分子所处环境变化和分子相互作用的能力,在生命科学、分子生物学和材料科学等研究领域中具有重要的应用前景.

Measuring the vibration dephasing time in molecular vibration is the free-mark method for detecting molecules harmlessly. Since molecular vibration refund processes are associated with molecular environment change, molecular vibration dephasing time also may reflect the substance＇s molecular environment change, which can be used to study the interaction between a certain molecule and its neighboring molecules. The molecular vibration spectrum and vibration dephasing time are obtained from the time-resolved coherent anti-stokes Raman scattering （CARS） simultaneously. Benzonitrile and methanol are used as samples for studying, the vibration dephasing time changes for the main vibration spectra when the environment changes. With benzonitrile mixed with anhydrous alcohol, its vibration dephasing time changes with environment are measured in three typical benzonitrile molecular vibrations 1017 cm-1, 2247 cm-1 and 3085 cm-1. For adjoining methanol molecular vibrations 2851 cm-1, and 2960 cm-1, vibration dephasing time changes are measured under environmental conditions. Results show that significant changes of molecular vibration dephasing time will take place in different environments. For a unidirectional molecular environment change, the molecular vibration dephasing time of benzonitrile is a one-way change, while the methanol molecule is of non-unidirectional vibration dephasing time change. But methanol molecules with vibration intensity ratios between two unidirectional changes with environment for I2851/I2960 are of a one-way change. By experimental measurement the vibration dephasing time of the main vibration mode of benzonitrile and methanol molecules varies with the changes in the environment, further understanding of differences on vibration dephasing time of molecular vibration spectra of adjacent and non-adjacent variations can explain the variation of vibration dephasing time of methanol molecules. This method has the ability of detecting molecular environment change and molecular interactions, and has an important application prospect in the field of life science, molecular biology, and material science etc..