Li Hao, Kelly Kevin F, Baldelli Steven
Department of Chemistry, University of Houston, Houston, Texas 77204-5003, USA.
Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, USA.
J Chem Phys. 2020 Nov 21;153(19):190901. doi: 10.1063/5.0022691.
Surface chemistry is notoriously difficult to study, in part, due to the decreased number of molecules that contribute to the properties compared to the bulk phase but often has significant effects on the chemical activity of the material. This is especially true in topics such as corrosion, catalysis, wetting, and many others in nature and industry. Sum frequency generation (SFG) spectroscopy was developed for interface studies due to its high molecular selectivity and surface sensitivity, which is quite useful to study the effects of structural inhomogeneity in microscopy. Compressive sensing (CS) combined with SFG spectroscopy minimizes the imaging time while still producing quality images. Selected systems are presented here to demonstrate the capability of CS-SFG microscopy. CS-SFG microscopy successfully distinguished the static monolayer molecular mixtures, the orientations and adsorption of adsorbed molecules by the dip-coating technique, and the localized CO behaviors on polycrystalline Pt electrodes. Further discussion includes dynamic imaging as a future direction in CS-SFG microscopy. As materials and surfaces become more complex, imaging with chemical contrast becomes indispensable to understanding their performance and CS-SFG microscopy seems highly beneficial in this respect.
表面化学研究起来 notoriously difficult，部分原因是与体相相比，对性质有贡献的分子数量减少了，但它往往对材料的化学活性有显著影响。在腐蚀、催化、润湿以及自然界和工业中的许多其他领域等主题中尤其如此。和频产生（SFG）光谱法因其高分子选择性和表面敏感性而被开发用于界面研究，这对于研究显微镜下结构不均匀性的影响非常有用。压缩感知（CS）与SFG光谱法相结合，在仍能产生高质量图像的同时，将成像时间减至最短。这里展示了选定的系统，以证明CS-SFG显微镜的能力。CS-SFG显微镜成功地区分了静态单层分子混合物、通过浸涂技术吸附分子的取向和吸附情况，以及多晶铂电极上的局部CO行为。进一步的讨论包括动态成像，这是CS-SFG显微镜未来的一个发展方向。随着材料和表面变得更加复杂，具有化学对比度的成像对于理解它们的性能变得不可或缺，而CS-SFG显微镜在这方面似乎非常有益。
