Enhanced Absorption within a Cavity. A Study of Thin Dye Layers with the Surface Forces Apparatus
Enhanced Absorption within a Cavity. A Study of Thin Dye Layers with the Surface Forces Apparatus
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增强腔内的吸收。
DOI：
10.1021/j100094a021
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
C. Helm
中科院分区：
文献类型：
--
作者：
C. Mueller;P. Maechtle;C. Helm
我们使用表面力装置研究了法布里-珀罗涉仪的透过率，该干涉仪由一层从溶液中吸附的薄染料层(几纳米罗丹明B)组成，并夹在两片等厚的云母片之间。在加入染料后，我们不仅考虑了共振波长的移动，还考虑了透射峰的高度和宽度，从而可以推导出腔参数。已知谐振波长下的腔参数，我们可以用简单的近似公式计算染料层的复介电常数，正如我们通过与基于更完整的矩阵公式的计算相比较所演示的那样。测量了几个分子层的吸收光谱，并在积分吸收的基础上确定了该薄层中的染料浓度。与溶液中的单体相比，光谱发生了明显的移动，这表明界面上的许多染料分子以二聚体的形式排列。我们现在可以在表面力装置中研究染料分子的相互作用。
We use the surface forces apparatus to investigate the transmission of a Fabry-Perot interferometer consisting of a thin dye layer (a few nanometers Rhodamine B) adsorbed from solution and sandwiched between two mica sheets of equal thickness. After adding the dye, we consider not only the shift of the resonance wavelength but alsothe height and width of the transmission peak; thus, we can deduce the cavity parameters. Knowing the cavity parameters at a resonance wavelength, we can calculate the complex dielectric constant of the dye layer with simple approximate formulas, as we demonstrate by comparison to calculations based on the more complete matrix formulation. The absorption spectrum of a few molecular layers was measured, and based on the integrated absorption, the dye concentrationin this thin layer was determined. The spectrum shows a pronounced shift compared to monomers in solution, suggesting that many dye molecules at the interface are arranged as dimers. We are now in the position to investigate the interaction of dye molecules within the surface forces apparatus.