High-Accuracy CO(2) Line Intensities Determined from Theory and Experiment

Area of Science:

• Atmospheric science
• Quantum chemistry
• Spectroscopy

Background:

• Remote sensing of atmospheric CO2 requires line intensity uncertainties of 0.5% or better.
• Existing laboratory measurements often exceed this uncertainty threshold.

Purpose of the Study:

• To provide accurate rotation-vibration line intensities for carbon dioxide (CO2).
• To meet the stringent accuracy requirements for atmospheric monitoring.
• To develop a foundation for comprehensive CO2 spectroscopic line lists.

Main Methods:

• Joint experimental and theoretical study.
• Ab initio quantum chemical calculations.
• Laboratory measurements of line intensities.

Main Results:

• Rotation-vibration line intensities for CO2 were determined with high accuracy.
• The accuracy achieved meets the requirements for remote sensing.
• The theoretical calculations are adaptable to various CO2 bands and isotopologues.

Conclusions:

• The study successfully provides CO2 line intensities with the necessary accuracy for atmospheric monitoring.
• The developed ab initio methods are versatile and applicable to a wide range of CO2 spectral features.
• This work will underpin the creation of detailed CO2 spectroscopic line lists for future climate research.