Probing Intermolecular Vibrational Symmetry Breaking in Self-Assembled Monolayers with Ultrahigh Vacuum Tip-Enhanced Raman Spectroscopy
Probing Intermolecular Vibrational Symmetry Breaking in Self-Assembled Monolayers with Ultrahigh Vacuum Tip-Enhanced Raman Spectroscopy
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DOI：
10.1021/jacs.7b10645
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发表时间：
2017-12-27
影响因子：
15
通讯作者：
Van Duynett, Richard P.
中科院分区：
文献类型：
--
作者：
Chiang, Naihao;Jiang, Nan;Van Duynett, Richard P.
超高真空尖端增强拉曼光谱 (UHV-TERS) 将扫描探针显微镜的原子级成像能力与表面增强拉曼光谱的单分子化学灵敏度和结构特异性相结合。在这里，我们将这些技术与理论相结合，揭示分子间相互作用对室温下吸附在单晶银基底上的 N-N'-双（2,6-二异丙基苯基）-苝-3,4: 9,10-双（二甲酰亚胺）（PDI）自组装单层振动光谱的影响。特别是，我们揭示了 Ag(111) 和 Ag(100) 表面上 PDI 模式的振动简并性的提升，其中最强烈的扰动模式与分子外围的最大振动幅度相关。这项工作表明 UHV-TERS 能够直接测量纳米尺度的分子相互作用。我们预计这些信息将促进对分子间相互作用对表面结合分子振动模式最重要影响的基本理解。
Ultrahigh vacuum tip-enhanced Raman spectroscopy (UHV-TERS) combines the atomic-scale imaging capability of scanning probe microscopy with the single-molecule chemical sensitivity and structural specificity of surface-enhanced Raman spectroscopy. Here, we use these techniques in combination with theory to reveal insights into the influence of intermolecular interactions on the vibrational spectra of a N-N'-bis(2,6-diisopropylphenyl)-perylene-3,4: 9,10-bis ( dicarboximide) (PDI) self-assembled monolayer adsorbed on single-crystal Ag substrates at room temperature. In particular, we have revealed the lifting of a vibrational degeneracy of a mode of PDI on Ag(111) and Ag(100) surfaces, with the most strongly perturbed mode being that associated with the largest vibrational amplitude on the periphery of the molecule. This work demonstrates that UHV-TERS enables direct measurement of molecule molecule interaction at nanoscale. We anticipate that this information will advance the fundamental understanding of the most important effect of intermolecular interactions on the vibrational modes of surface-bound molecules.