Using Raman Spectroscopy To Study The Effect Of Pressure On Chirality Molecule Vibration

The phenomenon of symmetry breaking widely exists in the universe, even is considered to be the source of all things in our world. As one of the most common phenomena in the symmetry breaking, chirality closely affects all the life activities of organisms and all aspects of human life. This work focuses on studying the effect of chiral material on the polarization of transmitted light with spectrum technology and trying to reveal the physical mechanism of the phenomenon of chiral molecule under high pressure. Around the research target, this thesis mainly divided into the following three parts:(1) Studying the optical activity of the chiral metamaterial composed of u-shaped holes array. We design u-shaped hole on metal film as the basic unit and regard a pair of this units which are face-to-face and placed orthogonally as artificial chiral molecule enantiomer. By adjusting the chirality of these artificial metal molecular can control the polarization direction of linear polarized light. This achievement deepens our understanding on the microscopic physical mechanism of the interaction between chiral molecules and polarized light which is helpful for us to use the polarization property of light to study the basis of nature chiral molecule.(2) Studying the effect of pressure on the enantiomer of α-pinene by Raman spectrum. We choose α-pinene as research object, by measuring and contrasting the Raman spectrum of its two enantiomers under high pressures, we find their Raman spectrums show different result under high pressure. According to the analysis of the change of vibration mode corresponding to the Raman peaks, we find that the molecular structures of l-α-pinene and r-α-pinene occur asymmetrical change with the pressure rising without any chemical bonds formed or broken. So the differences between the vibration modes of the two enantiomers are caused by the different effect of pressure on them. This achievement reveal the changing tendency of molecular structure of the enantiomers under high pressure which provide a new sight and method to study the effect of pressure on chiral molecules.(3) Trying to set up a high-pressure in-suit micro-Raman-optical-activity(ROA)-spectroscopy to characterize the law of structure change of chiral molecule under high pressure. By studying the principle of ROA instrument and combining with the condition of high pressure experiment, we have designed and set up a preliminary ROA instrument applied to high pressure experiment in order to get the law of structure change of chiral molecule under the compaction of high pressure, which is helpful to make new molecule material using pressure. We find its potential problem in the first time debugging and put forward a reasonable solution.In conclusion, we study the interaction between the polarized light and the structure of artifact metal and nature chiral molecule. Also, we try to use ROA spectroscopy to characterize the structure change of chiral molecule under high pressure. These work deepen people’s cognition to chirality and lay the foundation for using high pressure to study and make new molecule material.