The role of perturbations in the B-X UV spectrum of S2 in a temperature-dependent mechanism for sulfur mass independent fractionation

Hull, Alexander W.

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https://hdl.handle.net/2142/97028 Copy

Description

Title

The role of perturbations in the B-X UV spectrum of S2 in a temperature-dependent mechanism for sulfur mass independent fractionation

Author(s)

Hull, Alexander W.

Contributor(s)

• Ono, Shuhei
• Field, Robert W.

Issue Date

2017-06-19

Keyword(s)

Multiple potential energy surfaces

Abstract

Sulfur mass independent fractionation (S-MIF) describes anomalous sulfur isotope ratios commonly found in sedimentary rocks older than 2.45 billion years. These anomalies likely originate from photochemistry of small, sulfur-containing molecules in the atmosphere, and their sudden disappearance from rock samples younger than 2.45 years is thought to be correlated with a sharp rise in atmospheric oxygen levels. The emergence of atmospheric oxygen is an important milestone in the development of life on Earth, but the mechanism for sulfur MIF in an anoxic atmosphere is not well understood. In this context, we present an analysis of the B-X UV spectrum of S$_{2}$, an extension of work presented last year. The B state of S$_{2}$ is strongly perturbed by the nearby B” state, as originally described by Green and Western (1996). Our analysis suggests that a doorway-mediated transfer mechanism shifts excited state population from the short-lifetime B state to the longer-lifetime B” state. Furthermore, access to the perturbed doorway states is strongly dependent on the population distribution in the ground state. This suggests that the temperature of the Achaean atmosphere may have played a significant role in determining the extent of S-MIF.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/97028

DOI

https://doi.org/10.15278/isms.2017.MG08

Copyright and License Information

Copyright 2017 Alexander W. Hull

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