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Pressure-induced hydrogen bond symmetrisation in guyanaite, beta -CrOOH; evidence from spectroscopy and ab initio simulations

Sandro Jahn, Bernd Wunder, Monika Koch-Mueller, Leila Tarrieu, Michael Poehle, Anke Watenphul and Michael N. Taran
Pressure-induced hydrogen bond symmetrisation in guyanaite, beta -CrOOH; evidence from spectroscopy and ab initio simulations (in The 7th European conference on Mineralogy and spectroscopy, Monika Koch-mueller (editor), Michael Fechtelkord (editor), Vladimir Khomenko (editor) and Sergio Speziale (editor))
European Journal of Mineralogy (September 2012) 24 (5): 839-850

Abstract

Guyanaite, beta -CrOOH, is a structural analogue of the high-pressure oxyhydroxide phases delta -AlOOH and epsilon -FeOOH. Here, it was synthesized in piston-cylinder and multi-anvil press experiments at 4-13.5 GPa and 900-1100 degrees C. The deuterated phase beta -CrOOD was synthesized at 4 GPa and 600 degrees C. The samples were characterized at ambient conditions by X-ray diffraction, diffuse optical reflectance spectroscopy and infrared absorption (IR) spectroscopy. In addition, the structural evolution of beta -CrOOH and beta -CrOOD with increasing pressure up to about 20 GPa was studied by in situ IR spectroscopy in a diamond anvil cell (DAC). This investigation was complemented by first-principles calculations in the framework of the density-functional theory (DFT). A pronounced geometric isotope effect and very short O-H. . .O bond lengths of 2.497(3) Aa for beta -CrOOH and 2.541(3) Aa for beta -CrOOD are observed at ambient pressure. In the IR spectra, no bands show up above 2000 cm (super -1) , which indicates strong hydrogen bonding. The evolution of OH- and OD-related vibrational bands with pressure studied by IR spectroscopy shows a discontinuity at about 5 GPa. The DFT calculations suggest that this change in compression mechanism is related to a second-order phase transition from the low-pressure phase with asymmetric hydrogen positions (space group P2 (sub 1) nm or Pnnm) to a high-pressure phase with space group Pnnm that is characterized by symmetric hydrogen bonds with two identical OH bond lengths of 1.20(1) Aa. Using density functional perturbation theory, the most prominent high-frequency modes observed in the IR spectra are assigned to O-H-O bending vibrations. The transition pressure for hydrogen bond symmetrisation in beta -CrOOH is considerably lower than in other hydrous phases of recent interest, such as delta -AlOOH or phase D.


ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 24
Serial Issue: 5
Title: Pressure-induced hydrogen bond symmetrisation in guyanaite, beta -CrOOH; evidence from spectroscopy and ab initio simulations
Title: The 7th European conference on Mineralogy and spectroscopy
Author(s): Jahn, SandroWunder, BerndKoch-Mueller, MonikaTarrieu, LeilaPoehle, MichaelWatenphul, AnkeTaran, Michael N.
Author(s): Koch-mueller, Monikaeditor
Author(s): Fechtelkord, Michaeleditor
Author(s): Khomenko, Vladimireditor
Author(s): Speziale, Sergioeditor
Affiliation: German Research Centre for Geosciences, Potsdam, Germany
Affiliation: Deutsches GeoForschungsZentrum, Helmholtz-Zentrum Potsdam, Potsdam, Germany
Pages: 839-850
Published: 201209
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Germany
Meeting name: The 7th European conference on Mineralogy and spectroscopy
Meeting location: Potsdam, DEU, Germany
Meeting date: 20110904Sept. 4-7, 2011
References: 45
Accession Number: 2012-086347
Categories: Mineralogy of non-silicates
Document Type: Serial Conference document
Bibliographic Level: Analytic
Illustration Description: illus. incl. 4 tables
Secondary Affiliation: Ruhr-Universitaet Bochum, DEU, GermanyUniversite de Savoie, FRA, FranceDeutsches Elektronen-Synchrotron, DEU, GermanyNational Academy of Science of Ukraine, UKR, Ukraine
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, copyright, Schweizerbart'sche Verlagsbuchhandlung. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201245
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