17:15 〜 19:15
[AAS03-P04] High-Resolution UV Absorption Cross-Sections for Isotopic Studies: A New Spectroscopic Measurement Approach
キーワード：UV Spectroscopy, Absorption Cross-Sections, Photochemical Modeling, Isotopic Fractionation
Precise spectral data is crucial for isotopic studies in atmospheric chemistry and planetary science. In this study, we present high-resolution ultraviolet absorption cross-sections of carbon disulfide (CS2) in the 280-360 nm region, measured at 1 cm-1 resolution using a novel least absolute deviation (LAD) linear regression algorithm. This approach minimizes errors caused by noisy measured data, providing more accurate absorption cross-sections compared to conventional averaging methods (Grosch et al., 2015).
The new dataset significantly improves the accuracy and completeness of existing absorption spectra, particularly in the 330-360 nm range, where previous measurements suffered from low signal-to-noise ratios. By reducing propagated errors in derived photodissociation rate constants by two orders of magnitude, our data enhances the reliability of photochemical modeling of CS2 and its role in atmospheric sulfur cycles. The improved spectral resolution allows for a more detailed analysis of rovibrational transitions, which is essential for investigating isotopic fractionation effects.
Isotopic variations in sulfur-containing molecules such as CS2 play a key role in tracing sulfur fluxes, such as the diurnal variation of COS concentration for unknown reason (Kamezaki et al., 2025), and understanding mass-independent fractionation (MIF) processes in the atmosphere. The newly resolved spectral features offer insights into the influence of electronic transitions and vibronic coupling on isotopic shifts, which could enable more precise modeling of photochemical isotope effects. These findings have implications for stratospheric aerosol formation, planetary atmospheres, and geochemical sulfur cycling.
By providing high-accuracy absorption cross-sections and a replicable robust methodology for spectral analysis, this work lays the foundation for future isotopic investigations in sulfur chemistry. The LAD-based approach demonstrated here is broadly applicable to other molecular systems requiring high-precision spectral data, making it a valuable tool for atmospheric chemistry and astrophysics research.
References
Grosch, H., Fateev, A., & Clausen, S. (2015). UV absorption cross-sections of selected sulfur-containing compounds at temperatures up to 500 °C. Journal of Quantitative Spectroscopy and Radiative Transfer, 154, 28-34.
Kamezaki, K., Danielache, S. O., Ishidoya, S., Maeda, T., & Murayama, S. (2025). A Low-Power Continuous Measurement System for Atmospheric Carbonyl Sulfide Concentration and its Application to the Observation in Tsukuba, Japan. Journal of the Meteorological Society of Japan. Ser. II.
The new dataset significantly improves the accuracy and completeness of existing absorption spectra, particularly in the 330-360 nm range, where previous measurements suffered from low signal-to-noise ratios. By reducing propagated errors in derived photodissociation rate constants by two orders of magnitude, our data enhances the reliability of photochemical modeling of CS2 and its role in atmospheric sulfur cycles. The improved spectral resolution allows for a more detailed analysis of rovibrational transitions, which is essential for investigating isotopic fractionation effects.
Isotopic variations in sulfur-containing molecules such as CS2 play a key role in tracing sulfur fluxes, such as the diurnal variation of COS concentration for unknown reason (Kamezaki et al., 2025), and understanding mass-independent fractionation (MIF) processes in the atmosphere. The newly resolved spectral features offer insights into the influence of electronic transitions and vibronic coupling on isotopic shifts, which could enable more precise modeling of photochemical isotope effects. These findings have implications for stratospheric aerosol formation, planetary atmospheres, and geochemical sulfur cycling.
By providing high-accuracy absorption cross-sections and a replicable robust methodology for spectral analysis, this work lays the foundation for future isotopic investigations in sulfur chemistry. The LAD-based approach demonstrated here is broadly applicable to other molecular systems requiring high-precision spectral data, making it a valuable tool for atmospheric chemistry and astrophysics research.
References
Grosch, H., Fateev, A., & Clausen, S. (2015). UV absorption cross-sections of selected sulfur-containing compounds at temperatures up to 500 °C. Journal of Quantitative Spectroscopy and Radiative Transfer, 154, 28-34.
Kamezaki, K., Danielache, S. O., Ishidoya, S., Maeda, T., & Murayama, S. (2025). A Low-Power Continuous Measurement System for Atmospheric Carbonyl Sulfide Concentration and its Application to the Observation in Tsukuba, Japan. Journal of the Meteorological Society of Japan. Ser. II.