Department of Chemistry, University of Texas at Austin, Austin 78712, United States.
J Phys Chem A. 2021 Jul 29;125(29):6498-6504. doi: 10.1021/acs.jpca.1c04558. Epub 2021 Jul 14.
Ultrafast two-dimensional infrared (2D IR) spectroscopy and Fourier transform infrared (FTIR) spectroscopy are often performed in tandem, with FTIR typically used to interpret and provide hypotheses for 2D IR experiments. Comparisons between 2D IR and FTIR spectra can also be used to examine the structure and orientation in systems of coupled vibrational chromophores. The most common method for comparing 2D IR and FTIR lineshapes, the diagonal slice method, contains significant artifacts when applied to oscillators with low anharmonicities. Here, we introduce a new technique, the pump slice amplitude (PSA) method, for relating 2D IR lineshapes to FTIR lineshapes and compare PSAs against diagonal slices using theoretical and experimental spectra. We find that PSAs are significantly more similar to FTIR lineshapes than diagonal slices in systems with low anharmonicity.
超快二维红外（2D IR）光谱和傅里叶变换红外（FTIR）光谱通常是串联进行的，FTIR 通常用于解释和为 2D IR 实验提供假设。2D IR 和 FTIR 光谱之间的比较也可用于研究耦合振动发色团体系中的结构和取向。比较 2D IR 和 FTIR 线形的最常用方法，对角线切片法，在应用于具有低非谐性的振荡器时存在显著的伪影。在这里，我们引入了一种新的技术，即泵浦切片幅度（PSA）方法，用于将 2D IR 线形与 FTIR 线形相关联，并使用理论和实验光谱比较 PSA 与对角线切片。我们发现，在非谐性低的体系中，PSA 与 FTIR 线形的相似度显著高于对角线切片。
