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Chlorine Release From Common Chlorides by Martian Dust Activity
Author(s) -
Wang Alian,
Yan Yuanchao,
Jolliff Bradley L.,
McLennan Scott M.,
Wang Kun,
Shi Erbin,
Farrell William M.
Publication year - 2020
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
eISSN - 2169-9100
pISSN - 2169-9097
DOI - 10.1029/2019je006283
Subject(s) - x ray photoelectron spectroscopy , chlorine , chemistry , mars exploration program , raman spectroscopy , scanning electron microscope , spectroscopy , analytical chemistry (journal) , martian , chemical engineering , materials science , environmental chemistry , astrobiology , physics , organic chemistry , optics , quantum mechanics , composite material , engineering
Chlorine is one of the highly mobile elements that participated in early aqueous chemistry and later alteration in Mars history. Our new experimental results suggest that chlorine could cycle on present‐day Mars between the atmosphere and surface, driven by multiphase redox plasma chemistry induced by current Martian dust activity (dust storms, dust devils, and grain saltation). We present two sets of experimental results that demonstrate the instantaneous release of chlorine from seven common chlorides during a medium strength electrostatic discharge (ESD) process that induced plasma chemistry in a Mars environmental chamber. Results include (1) the direct detection of a plasma emission line at 837.8 nm of the first excited state of the Cl atom ( Cl‐I ) by in situ plasma spectroscopy during the ESD process for MgCl 2 , FeCl 2 , and AlCl 3 and (2) the characterization of Cl‐bearing phases in the films deposited on the upper electrode after 7 hr of ESD exposure on each of seven chlorides (NaCl, KCl, CaCl 2 , MgCl 2 , FeCl 2 , AlCl 3 , and FeCl 3 ), using Raman spectroscopy, X‐ray diffraction (XRD), scanning electron microscopy (SEM), energy‐dispersive X‐ray (EDX) spectroscopy, and X‐ray photoelectron spectroscopy (XPS). This study is part of a series of laboratory investigations on the Martian atmosphere and surface interaction induced by electrochemistry.