Luo Yang, Sheng Shaoxiang, Pisarra Michele, Martin-Jimenez Alberto, Martin Fernando, Kern Klaus, Garg Manish
Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany.
Dipartimento di Fisica, Università della Calabria, Via P. Bucci, Cubo 30C, 87036, Rende, CS, Italy.
Nat Commun. 2024 Aug 14;15(1):6983. doi: 10.1038/s41467-024-51419-1.
The capability to excite, probe, and manipulate vibrational modes is essential for understanding and controlling chemical reactions at the molecular level. Recent advancements in tip-enhanced Raman spectroscopies have enabled the probing of vibrational fingerprints in a single molecule with Ångström-scale spatial resolution. However, achieving controllable excitation of specific vibrational modes in individual molecules remains challenging. Here, we demonstrate the selective excitation and probing of vibrational modes in single deprotonated phthalocyanine molecules utilizing resonance Raman spectroscopy in a scanning tunneling microscope. Selective excitation is achieved by finely tuning the excitation wavelength of the laser to be resonant with the vibronic transitions between the molecular ground electronic state and the vibrational levels in the excited electronic state, resulting in the state-selective enhancement of the resonance Raman signal. Our approach contributes to setting the stage for steering chemical transformations in molecules on surfaces by selective excitation of molecular vibrations.
激发、探测和操纵振动模式的能力对于在分子水平上理解和控制化学反应至关重要。尖端增强拉曼光谱学的最新进展使得能够以埃级空间分辨率探测单个分子中的振动指纹。然而，在单个分子中实现对特定振动模式的可控激发仍然具有挑战性。在这里，我们展示了利用扫描隧道显微镜中的共振拉曼光谱对单个去质子化酞菁分子的振动模式进行选择性激发和探测。通过精细调节激光的激发波长，使其与分子基态电子态和激发电子态中的振动能级之间的振动-电子跃迁共振，从而实现选择性激发，导致共振拉曼信号的态选择性增强。我们的方法有助于通过选择性激发分子振动为引导表面分子中的化学转化奠定基础。
