title: Visualization of Vibrational Modes in Real Space by Tip-Enhanced Non-Resonant Raman Spectroscopy.
abstract: We present a general theory to model the spatially resolved non-resonant Raman images of molecules. It is predicted that the vibrational motions of different Raman modes can be fully visualized in real space by tip-enhanced non-resonant Raman scattering. As an example, the non-resonant Raman images of water clusters were simulated by combining the new theory and first-principles calculations. Each individual normal mode gives rise its own distinct Raman image, which resembles the expected vibrational motions of the atoms very well. The characteristics of intermolecular vibrations in supermolecules could also be identified. The effects of the spatial distribution of the plasmon as well as nonlinear scattering processes were also addressed. Our study not only suggests a feasible approach to spatially visualize vibrational modes, but also provides new insights in the field of nonlinear plasmonic spectroscopy.
authors.affiliation: Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, 10691, Stockholm, Sweden.
authors.forename: Sai
authors.identifier: http://orcid.org/0000-0002-3282-0711
authors.initials: S
authors.lastname: Duan
authors.affiliation: Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, 10691, Stockholm, Sweden.
authors.forename: Guangjun
authors.identifier: http://orcid.org/0000-0002-3915-300X
authors.initials: G
authors.lastname: Tian
authors.affiliation: Department of Theoretical Chemistry and Biology, School of Biotechnology, Royal Institute of Technology, 10691, Stockholm, Sweden. yiluo@ustc.edu.cn.|Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, 230026, Anhui, P. R. China. yiluo@ustc.edu.cn.
authors.forename: Yi
authors.identifier: http://orcid.org/0000-0003-0007-0394
authors.initials: Y
authors.lastname: Luo
keywords: Raman spectroscopy; ab initio calculations; surface chemistry; vibrational spectroscopy; water adsorption