Collision‐Induced Absorption of CH <sub>4</sub> ‐CO <sub>2</sub> and H <sub>2</sub> ‐CO <sub>2</sub> Complexes and Their Effect on the Ancient Martian Atmosphere
Paul J. Godin, Ramses M. Ramírez, Charissa Campbell, Tyler Wizenberg, Tue Giang Nguyen, Kimberly Strong, John E. Moores
Abstract
Abstract Experimental measurements of collision‐induced absorption (CIA) cross sections for CO 2 ‐H 2 and CO 2 ‐CH 4 complexes were performed using Fourier transform spectroscopy over a spectral range of 150–475 cm −1 and a temperature range of 200–300 K. These experimentally derived CIA cross sections agree with the spectral range of the calculation by Wordsworth et al. (2017) however, the amplitude is half of what was predicted. Furthermore, the CIA cross sections reported here agree with those measured by Turbet et al. (2019, 2019). Additionally, radiative transfer calculations of the early Mars atmosphere were performed, and showed that CO 2 ‐CH 4 CIA would require surface pressure greater than 3 bar for a 10% methane atmosphere to achieve 273 K at the surface. For CO 2 ‐H 2 , liquid water is possible with 5% hydrogen and less than 2 bar of surface pressure.