Raman spectroscopy study of manganese oxides

Raman spectra were collected for an extensive set of well-characterized tunnel-structure Mn oxide mineral species employing a range of data collection conditions. Using various laser wavelengths, such as 785, 633, and 532 nm at low power levels (30-500 µW), as well as the comprehensive database of standard spectra presented here, it is generally possible to distinguish and identify the various tunnel structure Mn oxide minerals. The Raman mode relative intensities can vary significantly as a function of crystal orientation relative to the incident laser light polarization direction as well as laser light wavelength. Consequently, phase identification success is enhanced when using a standards database that includes multiple spectra collected for different crystal orientations and with different laser light wavelengths. For the hollandite-group minerals, the frequency of the Raman mode near 630 cm-1 shows a strong linear correlation with the fraction of Mn3+ in the octahedral Mn sites. With the comprehensive Raman database of well-characterized Mn oxide standards provided here (and available online as Supplemental Materials1), and use of appropriate data collection conditions, micro-Raman is a powerful tool for identification and characterization of biotic and abiotic Mn oxide phases from diverse natural settings, including on other planets.

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Work Title Raman spectroscopy study of manganese oxides
Subtitle Tunnel structures
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Open Access
Creators
  1. Jeffrey E. Post
  2. David A. McKeown
  3. Peter J. Heaney
License In Copyright (Rights Reserved)
Work Type Article
Publisher
  1. American Mineralogist
Publication Date August 26, 2020
Publisher Identifier (DOI)
  1. https://doi.org/10.2138/am-2020-7390
Deposited December 01, 2021

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  • Created
  • Added Post_RamanMnOxidesTunnel_AmMin_2020.pdf
  • Added Creator Jeffrey E. Post
  • Added Creator David A. McKeown
  • Added Creator Peter J. Heaney
  • Published
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