Phasor Approach for identifying molecular concentration in gas absorption spectra
David A. Lopez Guardado1, Viktor V. Nikolaev1, Yury V. Kistenev1; 1Tomsk State University, Tomsk, Russia
Abstract
Accurate measurement of gas concentrations is critical for environmental monitoring, industrial safety, medical diagnostics, and scientific research. Usually, concentration is calculated by absorption spectra which is analyzed for gas detection using approximations of spectral lines shapes such as Gaussian, Lorentzian, Voigt, Spectral fitting, etc. However, this method presents certain limitations such as spectral overlap and the requirement of specialized instruments to filter noise. In this study, it is presented the phasor approach for the analysis of gas concentration in absorption spectra. Phasor approach has proven itself efficient in processing fluorescence attenuation curves of FLIM data. The Lorentzian shape line function describes the absorption lines in the spectra. The Integral Fourier Transformation allowed us to switch from this shape line function to an attenuation function. After this, the concentration was determined by using the graphical representation of the phasor approach. Firstly, we use modeled line shapes based on the Lorentzian shape line function. We observed the transformation of single and double absorption spectral lines with 4 changing variables: Intensity, linewidth, center of the line and domain. This part of the study showed that the phasor approach produces different representations when any of the 4 variables are changed. Secondly, the phasor approach method was applied to modeled spectra from a gas mixture and its pure gases. These gases generated vectors in the phasor plane. It was found that the distances in the phasor plane between a gas mixture and its pure components changed according to the concentration of the gas. These findings suggest the possibility of creating a method that provides a metric for the identification of gas concentration.
This research was funded by the Ministry of Science and Higher Education of the Russian Federation grant number 075-15-2024-557 dated 04/25/2024.
Speaker
David A. Lopez Guardado
Tomsk State University
Russia
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