Kraack Jan Philip, Hamm Peter
Department of Chemistry, University of Zurich , Winterthurerstrasse 190, CH-8057, Zurich, Switzerland.
Chem Rev. 2017 Aug 23;117(16):10623-10664. doi: 10.1021/acs.chemrev.6b00437. Epub 2016 Dec 1.
Ultrafast two-dimensional infrared spectroscopy (2D IR) has been advanced in recent years toward measuring signals from only a monolayer of sample molecules at solid-liquid and solid-gas interfaces. A series of experimental methods has been introduced, which in the chronological order of development are 2D sum-frequency-generation (2D SFG), transmission 2D IR, and reflection 2D IR, the latter in either internal, attenuated total reflection (ATR), or external reflection configuration. The different variants of 2D vibrational spectroscopy are based on either the even-order or the odd-order nonlinear susceptibility, and all allow resolving similar molecular temporal and spectral information. In this review, we introduce the basic principles of the different methods of 2D vibrational spectroscopy at surfaces along with a balanced overview on the technological aspects as well as benefits and shortcomings. We furthermore discuss the current scope of applications for 2D vibrational surface spectroscopy, which spans an impressively broad range of samples from biological molecules to heterogeneous catalysts. The emphasis is on the ultrafast structural dynamics of molecules at interfaces, environmental interactions, and intermolecular interactions. We furthermore consider important recent technological developments of 2D vibrational surface spectroscopy, which employ (i) surface enhancement, (ii) methods for studying electrochemical interfaces, and (iii) extensions for resolving nonequilibrium processes (transient 2D IR). A detailed outlook is finally given regarding important future applications and technological developments of 2D vibrational surface spectroscopy.
近年来，超快二维红外光谱（2D IR）已取得进展，能够测量固液和固气界面仅单层样品分子的信号。已引入了一系列实验方法，按发展时间顺序依次为二维和频产生（2D SFG）、透射二维红外光谱以及反射二维红外光谱，后者可采用内反射、衰减全反射（ATR）或外反射配置。二维振动光谱的不同变体基于偶数阶或奇数阶非线性极化率，并且都能够解析相似的分子时间和光谱信息。在本综述中，我们介绍了表面二维振动光谱不同方法的基本原理，并对技术方面以及优缺点进行了全面概述。我们还讨论了二维振动表面光谱当前的应用范围，其涵盖了从生物分子到多相催化剂等令人印象深刻的广泛样品。重点在于界面处分子的超快结构动力学、环境相互作用和分子间相互作用。我们还考虑了二维振动表面光谱近期的重要技术发展，其中包括（i）表面增强、（ii）研究电化学界面的方法以及（iii）用于解析非平衡过程的扩展（瞬态二维红外光谱）。最后，针对二维振动表面光谱未来的重要应用和技术发展给出了详细展望。
