Intermolecular Interactions at the Silica–Liquid Interface Modulate the Fermi Resonance Coupling in Surface Methanol
Intermolecular Interactions at the Silica–Liquid Interface Modulate the Fermi Resonance Coupling in Surface Methanol
复制标题
二氧化硅与液体界面的分子间相互作用调节表面甲醇中的费米共振耦合
DOI：
10.1021/acs.jpclett.1c01015
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Velarde, Luis
中科院分区：
文献类型：
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作者：
Bui, Thomas T.;Colón, Luis A.;Velarde, Luis
用振动和频产生（vSFG）光谱研究了亲水性熔融石英与乙腈（MeCN）和甲醇（MeOH）二元混合溶剂之间的埋固/液界面。我们的数据表明，在高的相对浓度的甲醇，费米共振峰的vSFG光谱大大抑制，它逐渐获得强度的甲醇用全氘代乙腈稀释。这种现象是量化的费米共振耦合系数，W，提取使用一个两级模型，以及实验强度比，R，甲基费米共振带的对称拉伸。在1.0 MeOH摩尔分数下，WandR值分别为10 ± 10 cm-1和0.01 ± 0.02，而在0.1摩尔分数下，WandR分别增加到46 ± 4 cm-1和0.43 ± 0.16。这表明，溶剂化与乙腈有效地调谐费米耦合的甲醇振动在二氧化硅/液体界面。
The buried solid/liquid interface between hydrophilic fused silica and binary solvent mixtures of acetonitrile (MeCN) and methanol (MeOH) was studied with vibrational sum-frequency generation (vSFG) spectroscopy. Our data showed that at high relative concentrations of methanol, the Fermi resonance peak in the vSFG spectrum is greatly suppressed, and it progressively gains intensity as methanol is diluted with perdeuterated acetonitrile. This phenomenon is quantified by the Fermi resonance coupling coefficient,W, extracted using a two-level model, as well as the experimental intensity ratio,R, of the methyl Fermi resonance band to that of the symmetric stretch. At a 1.0 MeOH mole fraction,WandRvalues were 10 ± 10 cm–1and 0.01 ± 0.02, respectively, whereas at a 0.1 mole fraction,WandRincreased to 46 ± 4 cm–1and 0.43 ± 0.16, respectively. This indicates that solvation with acetonitrile effectively tunes the Fermi coupling of methanol vibrations at the silica/liquid interface.