title: Reflection spectra of bio-organic materials in the 2.5-4 micron region and the interpretation of the infrared spectrum of Mars.
abstract: The nature and assignment of the Martian spectral features observed by W. M. Sinton in the 3-4 micron region have been re-examined. It is shown that it is not possible to state unequivocally that there are absorption bands at 2710 (3.69 microns), 2790 (3.58 microns) and 2900 (3.45 microns) cm-1. Rather the possibility of the presence of true reflection features complicates the issue and enables only a wide range to be specified for the corresponding resonant frequencies. To clarify the assignment of these a large number of pure organic and inorganic solids, together with a selection of biological samples, have been recorded in reflection. The assignment of the features to organic matter, implying the presence of life on the Martian maria, is found to be improbable. While inorganic carbonates have bands in this region, they also do not provide a satisfactory explanation of the observations. The assignment of these Martian spectral features is then an open question.
authors.affiliation: Space Sciences Laboratory and Department of Chemistry, University of California, Berkeley Calif., USA.
authors.forename: D G
authors.initials: DG
authors.lastname: Rea
authors.forename: T
authors.initials: T
authors.lastname: Belsky
authors.forename: M
authors.initials: M
authors.lastname: Calvin
mesh_terms: D055580:Astronomical Phenomena; D001256:Astronomy; D018559:Exobiology; D005118:Extraterrestrial Environment; D018535:Mars; D013055:Spectrophotometry, Infrared