³²S, ³³S, ³⁴S, and ³⁶S Sulfur Dioxide B1B1-X1A1 Absorption Band Measurement Using LAD Regression

Abstract

This study provides a new idea on data processing by correcting the linear relationship between the absorbance and sample concentration according to the Beer-Lambert law using the least absolute deviation (LAD) method to exclude the effect of random noise on the data fit. The spectrum resolution in this study is 0.4 cm^-1. Instrument optics and Fast Fourier Transform (FFT) setups were optimized for high-resolution measurements. The UV absorption cross-section of each SO₂ sulfur stable isotopologue was presented and the isotopic effect was also discussed. In addition, the raw interferograms were recorded, where the FFT can be applied to generate lower-resolution spectrums. Therefore, the relationship between spectrum resolution and the isotopic effect was discussed.