A Model Study of Chamber Photochemical Experiments for S-MIF Under Reducing Conditions

Abstract

The Archean era is important for understanding the evolution of our planet and Earth-like exoplanets. Sulfur Mass-Independent Fractionation (S-MIF) has been widely applied as a geochemical tracer that can provide chemical and physical clues for the state of a given atmosphere. To understand thoroughly the enrichment processes of stable sulfur isotopes and the S-MIF photochemical mechanisms in chamber photochemical experiments under reducing conditions, a 1D photochemical model for the S-MIF generation mechanism inside a chamber was developed by using the Krome package[1]. All related chemical reactions to the chamber photochemical experiment of 32S, 33S, 34S, 36S isotope species were added to the model. Three main proposed mechanisms of S-MIF such as the wavelength effect, self-shielding effect, and intersystem crossing effect were also included. Experimental data[2], [3] were used for model validation. Although there are several issues with the Archean S-MIF sources and large differences between the experiment data and the rock record. This model can quantify the contribution of each reaction to the total S-MIF measured during experiments.