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arXiv · 2608.01698

Tip-Enhanced Vibrational Ladder Climbing in Surface Molecular System

Tatsuto Mochizuki·Shota Takahashi·Atsunori Sakurai·Toshiki Sugimoto
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Abstract

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.

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Tatsuto Mochizuki, Shota Takahashi, Atsunori Sakurai, Toshiki Sugimoto. 2026-08-03. Tip-Enhanced Vibrational Ladder Climbing in Surface Molecular System. https://arxiv.org/abs/2608.01698

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