Developing Correction Methods by Revisiting the Concept of Effective Thickness in Attenuated Total Reflection...

Area of Science:

• Spectroscopy
• Physical Chemistry
• Materials Science

Background:

• Attenuated total reflection (ATR) spectroscopy is crucial for analyzing samples with low absorption.
• The effective thickness concept, introduced by Hansen and Harrick, is vital for quantitative ATR analysis.
• Existing methods for effective thickness derivation can be complex and may lack precision for certain materials.

Purpose of the Study:

• To develop a more straightforward derivation of effective thickness in ATR spectroscopy.
• To improve estimations of effective thickness for s- and p-polarized light.
• To enhance existing ATR correction schemes and introduce a novel spectral correction method.

Main Methods:

• A novel derivation of effective thickness following Hansen's approach, incorporating an intermediate approximation.
• Application of Fresnel's equations for validation, particularly for organic and biological materials.
• Development of a Kramers-Kronig transformed absorbance-based correction scheme.

Main Results:

• A more straightforward derivation of effective thickness was achieved.
• Improved estimations for effective thicknesses with s- and p-polarized light were obtained.
• A new correction scheme utilizing Kramers-Kronig transformed absorbance was introduced, addressing spectral shifts.

Conclusions:

• The new derivation provides more accurate effective thickness estimations, especially for organic and biological samples.
• The enhanced ATR correction scheme improves quantitative analysis in ATR spectroscopy.
• The Kramers-Kronig based correction shows potential for advanced spectral analysis, including pattern recognition and identification.