High accuracy CO$_2$ line intensities determined from theory and experiment

TL;DR

This paper combines experimental and theoretical methods to determine highly accurate CO₂ line intensities, essential for precise atmospheric remote sensing, surpassing the accuracy of most existing measurements.

Contribution

It presents a joint experimental and ab initio theoretical approach to accurately determine CO₂ line intensities, enabling comprehensive spectroscopic line lists for atmospheric studies.

Findings

Achieved line intensity uncertainties below 0.5%

Extended ab initio calculations to all relevant CO₂ bands and isotopologues

Provided data crucial for improving remote sensing accuracy

Abstract

Atmospheric CO$_2$ concentrations are being closely monitored by remote sensing experiments which rely on knowing line intensities with an uncertainty of 0.5\%\ or better. Most available laboratory measurements have uncertainties much larger than this. We report a joint experimental and theoretical study providing rotation-vibration line intensities with the required accuracy. The {\it ab initio} calculations are extendible to all atmospherically important bands of CO$_2$ and to its isotologues. As such they will form the basis for detailed CO$_2$ spectroscopic line lists for future studies.