液态水的自发与受激表面增强拉曼散射
Spontaneous versus Stimulated Surface-Enhanced Raman Scattering of Liquid Water.
作者信息
Filipczak Paulina, Pastorczak Marcin, Kardaś Tomasz, Nejbauer Michał, Radzewicz Czesław, Kozanecki Marcin
机构信息
Department of Molecular Physics, Faculty of Chemistry, Lodz University of Technology, Zeromskiego 116, 90-924 Lodz, Poland.
Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland.
出版信息
J Phys Chem C Nanomater Interfaces. 2021 Jan 28;125(3):1999-2004. doi: 10.1021/acs.jpcc.0c06937. Epub 2020 Dec 11.
We have observed for the first time the surface-enhanced (SE) signal of water in an aqueous dispersion of silver nanoparticles in spontaneous (SERS) and femtosecond stimulated Raman (SE-FSRS) processes with different wavelengths of the Raman pump (515, 715, and 755 nm). By estimating the fraction of water molecules that interact with the metal surface, we have calculated enhancement factors (EF): 4.8 × 10 for SERS and (3.6-3.7) × 10 for SE-FSRS. Furthermore, we have tested the role of simultaneous plasmon resonance and Raman resonance conditions for the a + bν overtone mode of water (755 nm) in SE-FSRS signal amplification. When the wavelength of the Raman pump is within the plasmon resonance of the metal nanoparticles, the Raman resonance has a negligible effect on the EF. However, the Raman resonance with the a + bν mode strongly enhances the signal of the fundamental OH stretching mode of water.
我们首次在银纳米颗粒水分散体中，于自发拉曼散射（SERS）以及不同拉曼泵浦波长（515、715和755 nm）的飞秒受激拉曼散射（SE-FSRS）过程中观测到了水的表面增强（SE）信号。通过估算与金属表面相互作用的水分子比例，我们计算出了增强因子（EF）：SERS为4.8×10，SE-FSRS为(3.6 - 3.7)×10。此外，我们测试了在SE-FSRS信号放大过程中，同时存在的等离子体共振和拉曼共振条件对水的a + bν泛音模式（755 nm）的作用。当拉曼泵浦波长处于金属纳米颗粒的等离子体共振范围内时，拉曼共振对增强因子的影响可忽略不计。然而，与a + bν模式的拉曼共振会强烈增强水的基本OH伸缩模式的信号。
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