AI 中文总结
该研究在扫描隧道显微镜的针尖-基底纳米间隙中，通过TE-SFG检测到Pt(111)表面CO的振动阶梯爬升，证明TE-SFG可用于探测该过程，为纳米尺度控制振动激发提供了新途径。
AI 中文摘要
实现高振动能级对于主动控制分子反应至关重要。我们展示了吸附在Pt(111)上的CO在扫描隧道显微镜形成的等离激元针尖-基底纳米间隙内的振动阶梯爬升，通过针尖增强和频产生（TE-SFG）进行检测。随着红外脉冲能量增加，热带峰依次出现直至3-4跃迁，表明更高振动能级的逐步布居。利用光学布洛赫方程的数值分析捕捉了这些特征的能量依赖性。这些结果证明了TE-SFG探测表面分子体系振动阶梯爬升的能力，并为获取高振动能级和在纳米尺度控制振动激发提供了有前景的途径。
英文摘要
Achieving high-lying vibrational states is essential for actively controlling molecular reactions. We demonstrate vibrational ladder climbing of CO adsorbed on Pt(111) within the plasmonic tip-substrate nanogap formed in a scanning tunneling microscope, detected via tip-enhanced sum-frequency generation (TE-SFG). As the infrared pulse energy increases, hot-band peaks appear sequentially up to the 3-4 transition, indicating the stepwise population of higher vibrational states. Numerical analysis using the optical Bloch equations captures the observed energy dependence of these features. These results demonstrate the capability of TE-SFG to probe vibrational ladder climbing in surface molecular systems and suggest a promising route toward accessing high-lying vibrational states and controlling vibrational excitation at the nanoscale.
