Liu Pengchong, Chen Xing, Ye Hepeng, Jensen Lasse
Department of Chemistry , Pennsylvania State University , University Park , Pennsylvania 16802 , United States.
ACS Nano. 2019 Aug 27;13(8):9342-9351. doi: 10.1021/acsnano.9b03980. Epub 2019 Jul 22.
Vibrational modes of a single molecule can be visualized by tip-enhanced Raman spectroscopy with atomic resolution. However, the exact vibrations associated with these Raman scattering images are still in debate due to the lack of theoretical interpretation. In this work, we systematically study the Raman scattering images of a single Co(II)-tetraphenylporphyrin molecule. The stable structure whose Raman scattering images consistently match experimental results is discovered. Furthermore, we elucidate the effects of near-field localizations and field gradient on the resolution in Raman scattering images. The approach of locally integrated Raman polarizability density employed in this work provides an intuitive explanation of the origin of the experimental Raman scattering images.
单分子的振动模式可以通过具有原子分辨率的针尖增强拉曼光谱进行可视化。然而，由于缺乏理论解释，与这些拉曼散射图像相关的确切振动仍存在争议。在这项工作中，我们系统地研究了单个钴（II）-四苯基卟啉分子的拉曼散射图像。发现了其拉曼散射图像与实验结果一致的稳定结构。此外，我们阐明了近场局域化和场梯度对拉曼散射图像分辨率的影响。这项工作中采用的局部积分拉曼极化率密度方法为实验拉曼散射图像的起源提供了直观的解释。
