A spectroscopic perturbation origin for sulfur mass independent fractionation via the B-X system of S2

Hull, Alexander W.

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https://hdl.handle.net/2142/100717 Copy

Description

Title

A spectroscopic perturbation origin for sulfur mass independent fractionation via the B-X system of S2

Author(s)

Hull, Alexander W.

Contributor(s)

• Field, Robert W.
• Ono, Shuhei

Issue Date

2018-06-22

Keyword(s)

Atmospheric science

Abstract

The Great Oxygenation Event (GOE), the introduction of O2 into the Earth’s atmosphere approximately 2.4 billion years ago, is a critical signpost in the development of life on Earth. The vanishing of sulfur isotope anomalies, called Sulfur Mass-Independent Fractionation (S-MIF), in the rock record is thought to be correlated with oxygenation of the early atmosphere. However, the mechanism for the generation of S-MIF in an anoxic atmosphere is unknown. Here, I propose a mechanism that involves spectroscopic perturbations in the B-X UV band system of S2. This proposal is based on a global deperturbation analysis done by Green and Westerna b and work that I presented previously at this conference in 2015 (MG12) and 2016 (MG08). Specifically, perturbations of the “bright” B state by a “dark” B” state cause some isotopologues to have longer average excited state lifetimes than others. I demonstrate a difference between the shorter-lifetime symmetric (e.g. 32S-32S) isotopologues of S2, for which nuclear permutation symmetry causes half of the rotational lines to be missing, and the longer-lifetime asymmetric isotopologues (e.g. 33S-32S). I also comment on general features of the B/B” system of S2 that make it uniquely well-suited to generate a large MIF isotope effect.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/100717

DOI

10.15278/isms.2018.FF03

Copyright and License Information

Copyright 2018 Alexander W. Hull

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