Theory

Calculated reflectance of ATR-IR from complex refractive index

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The experimental geometry is described by the two-layer model in the above Figure, where phase $i$ and phase $j$ represent the substrate and sample, respectively.

The incident light in phase $i$ and transmitted light in phase $j$ are related by Snell's law

$n_{i}\sin \theta _{i}=n_{j}\sin \theta _{j}$

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Fitting procedure| How to Fit the ATR-IR spectra

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Automatically determine the initial parameters in fitting procedure