单分子振动光谱与成像

Kangkai Liang1,2†, Zihao Wang1,2†, Weike Quan1,2†, Yueqing Shi1†, Hao Zhou1,2†, Liya Bi1,2†, Zhiyuan Yin1, Nathan Romero1, Mark Young1, Shaowei Li1,2,3* Probing vibrations at the single-molecule level is essential for achieving bond-specific chemical control in realistic heterogeneous environments. Here, we introduce a new measurement scheme that integrates frequency-tunable infrared excitation with scanning tunneling microscopy to characterize vibration-mediated nuclear motions of single molecules. We first validated the technique by monitoring the infrared-induced rotation of the ethynyl radical and then applied it to mapping pyrrolidine’s conformational dynamics. The resulting broadband spectra captured fundamental vibrational modes together with rich overtone and combination bands inaccessible by conventional methods, which we confirmed with isotopic substitutions. …