原位同步精密测量分子拉曼和红外振动光谱的新技术

Based on the linear and nonlinear principle of surface plasmon, we built up high vacuum tip-enhanced Raman spectroscopy. We can in suit and simultaneously measure molecular Raman and IR-active vibration, where the Raman spectra is based on the linear surface plasmon, and the intensity can reach upto 10^7; while the IR-active mode is based on the nonlinear surface plasmon, and can get the same order intensity. Up to now, no commercial instruments can perform in suit simultaneously measurement for Raman and IR-active vibrational spectra. Only our home-made instrument can perform it, since the year of 2013. Such measurements can significantly improve the spectra precision. Using this founding, we build up a new system of tip-enhanced Raman spectroscopy in unltra high vacuum, low temperature condition. Using such new instrument, we not only provide in suit simultaneously Raman and IR-active modes, but also can provide molecular scanning tunneling imaging and scanning tunneling spectroscopy, which can provide new method for analysis.

我们基于表面等离激元的线性和非线性原理,建立具有自主知识产权的高真空针尖增强拉曼光谱仪.可以原位同时测量微量分子的拉曼和红外振动分辨的光谱. 其中拉曼光谱是有表面等离激元的线性原理增强,可以达到10^7.红外振动光谱是由表面等离激元的非线性原理(表面等离激元梯度)增强的,强度可以达到和拉曼光谱相同的强度.目前所有商业化的还只能分别测量拉曼和红外振动,只有我们自主研发的高真空针尖增强拉曼光谱仪可以原位同时测量分子3N-6个振动模式,这样极大的提高了光谱检测的振动信息,特别是可以满足原位同时微量精确检测的要求.应用本基金的支持,我们将重新自主研发一套超高真空,低温(约4K)的针尖增强拉曼光谱仪。这样,可以不但在原位同时给出拉曼和红外振动光谱信息,还可以原位同时提供分子的扫描隧道图象和扫描隧道谱的分析新手段.

本项目研究分子拉曼光谱的精确测量，利用表面等离激元的电磁场增强分子拉曼光谱，利用高真空针尖增强拉曼光谱仪，实现了分子拉曼光谱的10的9次方的增强，实验和理论证明针尖增强拉曼光谱仪的光学分辨率达到1纳米。不但实现了基于电磁场增强的拉曼光谱增强，而且实现了基于表面等离激元电磁场梯度效应的红外振动光谱的探测。理论结合实验证明，当针尖和基地表面的距离在1纳米以内时，电场梯度的强度和电场本身的强度已经完全可以比拟，可以实现原位拉曼光谱和红外振动光谱的精确测量。我们工作得到国际社会关注，受美国化学会，荷兰爱思唯尔出版社，英国皇家化学会的邀请撰写相关领域的展望和综述。我们发表SCI国外科研论文36篇，发表英文专著一本，获得省部2等级奖一项（个人排名第二）。