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Can perchlorates be transformed to hydrogen peroxide (H 2 O 2 ) products by cosmic rays on the Martian surface?
Author(s) -
Crandall Parker B.,
Góbi Sándor,
GillisDavis Jeffrey,
Kaiser Ralf I.
Publication year - 2017
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
eISSN - 2169-9100
pISSN - 2169-9097
DOI - 10.1002/2017je005329
Subject(s) - oxidizing agent , hydrogen peroxide , regolith , deuterium , chemistry , perchlorate , martian surface , hydrogen , martian , peroxide , astrobiology , oxygen , inorganic chemistry , analytical chemistry (journal) , ion , environmental chemistry , mars exploration program , physics , atomic physics , organic chemistry
Abstract Due to their oxidizing properties, perchlorates (ClO 4 − ) are suggested by the planetary science community to play a vital role in the scarcity of organics on the Martian surface. However, alternative oxidation agents such as hydrogen peroxide (H 2 O 2 ) have received surprisingly little attention. In this study, samples of magnesium perchlorate hexahydrate (Mg(ClO 4 ) 2 · 6H 2 O) were exposed to monoenergetic electrons and D 2 + ions separately, sequentially, and simultaneously to probe the effects of galactic cosmic ray exposure of perchlorates and the potential incorporation of hydrogen (deuterium) into these minerals. The experiments were carried out under ultrahigh‐vacuum conditions at 50 K, after which the samples were slowly heated to 300 K while the subliming products were monitored by a quadrupole mass spectrometer. In all cases, molecular oxygen (O 2 ) was detected upon the onset of irradiation and also during the warmup phase. In case of a simultaneous D 2 + ‐electron exposure, deuterated water (D 2 O) and deuterium peroxide (D 2 O 2 ) were also detected in the warmup phase, whereas only small amounts of D 2 O 2 were found after an exclusive D 2 + irradiation. These experiments yield the first data identifying hydrogen peroxide as a potential product in the interaction of cosmic rays with perchlorates in the Martian regolith revealing that perchlorates are capable of producing multiple oxidizing agents (O 2 and D 2 O 2 ) that may account for the destruction of organics on the Martian surface.