Deep‐Ultraviolet (DUV) Raman and Fluorescence of Perchlorates and Chlorates: Implications for the Detection of Oxychlorines by the SHERLOC Instrument in Jezero Crater, Mars

Abstract Oxychlorines (i.e., perchlorates (ClO 4 − ) and chlorates (ClO 3 − )) have been detected by several landed missions on Mars at various locations. These missions have provided crucial information about the geographic distribution and abundances of oxychlorines on Mars but have not definitively identified the cation and anion type of in situ, solid oxychlorines. By speciating and precisely locating oxychlorines in Martian rocks, we may be able to better interpret the aqueous history of the rocks, understand the chlorine cycle on Mars, understand the chlorine isotope systematics on Mars, identify the potential for liquid brines on the surface, and advance in situ resource utilization activities for future robotic or landed missions. The Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument on the Mars 2020 Perseverance rover may have the ability to identify oxychlorine species (i.e., cation and anion) in solid surface targets due to their characteristic Raman and fluorescence bands. Additionally, the location and distribution of oxychlorines within rocks can be determined using the Autofocus and Context Imager (ACI) or Wide Angle Topographic Sensor for Operations and eNgineering (WATSON) camera, a subsystem of SHERLOC that provides high‐resolution, close‐up images of targets analyzed by the SHERLOC Deep‐Ultraviolet Raman spectrometer. The overarching goal of this work is to test SHERLOC's ability to identify and differentiate oxychlorine species in synthetic pure and natural mixed samples using a laboratory analog to the SHERLOC Raman and fluorescence spectrometer, identify instrumental limitations, and to further constrain potential detections made within Jezero crater, Mars.