Palik E D, Gibson J W, Holm R T, Hass M, Braunstein M, Garcia B
Appl Opt. 1978 Jun 1;17(11):1776-85. doi: 10.1364/AO.17.001776.
Some problems which arise in the characterization of surfaces and coatings by internal reflection spectroscopy are described. The ir spectra of bare CaF(2) trapezoids and of ThF(4)- and ZnSe-coated trapezoids exhibit absorption bands in the same spectral region as those of H(2)O and hydrocarbon impurities. In accord with previous investigations, it is observed that the absorptance due to water is much greater in the ThF(4) films than in the ZnSe films or on the CaF(2) surfaces. These results suggest that the water is distributed throughout the ThF(4) films, whereas for ZnSe it resides primarily on the surface. In addition, a number of interesting observations on the desorption and adsorption of water and hydrocarbons to these materials are made. The experimentally observed absorptances are analyzed on the basis of the reflectance for a threelayer system. The analysis enables reasonably quantitative values for the absorption coefficient to be determined for these thin-film coatings.
描述了通过内反射光谱法表征表面和涂层时出现的一些问题。裸露的CaF₂梯形晶体以及涂覆有ThF₄和ZnSe的梯形晶体的红外光谱在与H₂O和烃类杂质相同的光谱区域显示出吸收带。与先前的研究一致，观察到ThF₄薄膜中由于水引起的吸光度比ZnSe薄膜或CaF₂表面上的吸光度大得多。这些结果表明，水分布在整个ThF₄薄膜中，而对于ZnSe，水主要存在于表面。此外，还对水和烃类在这些材料上的解吸和吸附进行了一些有趣的观察。根据三层系统的反射率对实验观察到的吸光度进行了分析。该分析能够确定这些薄膜涂层吸收系数的合理定量值。
