Vibrational Spectroscopy of Ethane: Implications for Tropospheric and Planetary Chemistry

Abstract

As the simplest saturated non-methane Hydrocarbon (NMHC), Ethane (C2H6) is often used as a benchmark molecule to provide insights on internal motions around the C-C bond in complex biological molecules. Sharing similar and concurrent anthropogenic emission sources with methane (CH4), C2H6 is ubiquitous in Earth's atmosphere, with surface atmospheric mixing ratios ranging from 500 to 2200 ppt over the Northern Hemisphere as of the year 2015. The recent detection of C2H6 in the atmosphere of Jupiter, Saturn, and Titan through the v9 degenerate fundamental vibrational band cantered at ~822 cm-1 has elicited a lot of attention by planetary scientists leading to rigorous searches of other vibrational signatures of C2H6 in planetary atmospheres. In this poster, we present detailed analysis of C2H6 ro-vibrational spectra in the mid and near IR window using a natural gas sample. A CH4:C2H6 branching ratio is estimated based on selected portions of the ro-vibrational spectra of methane and ethane.