Abstract
The optical spectra of dravite (tourmaline) with an unusually high ratio of Fe3+ to Fe2+ and a synthetic elbaite with high Fe3+ content were studied at high temperature (297 to 600 K) and high pressure (to 10.51 GPa) conditions. Individual absorption bands derived from paired Fe atoms were identified in the spectra and their temperature and pressure dependence was studied. The most pronounced effects are the intensification of the two Fe2+-related bands (~9090 cm-1 and ~14300 cm-1) at pressure, their shift to higher energy at pressure, and their pronounced intensity decrease with increasing temperature. Such behavior is assumed to be caused by an electronic exchange interaction in an Fe2+-Fe3+ pair at adjacent Y sites in the structure.
Temperature and pressure dependencies of the bands attributed to Fe3+-Fe3+ exchange-coupled pairs are noticeably different from those of Fe2+-Fe3+ pairs. This shows that the two types of pairs have different exchange interactions, and points to the need for further experimental and theoretical investigation. The intensity of the intense E⊥c-polarized band at ~ 20580 cm-1 originating from the 6A1g → (4A1g, 4Eg) transition of the Fe3+(Y)-Fe3+(Y) pair, depends moderately on temperature and pressure.
The intensity of a weak shoulder at ~18350 cm-1 (E⊥c), also attributed to an Fe3+(Y)-Fe3+(Y) pair, decreases and nearly disappears between 5.44 and 9.55 GPa. The intensity of the E⊥c-polarized band at ~18500 cm-1, attributed to an Fe3+(Z)-Fe3+(Z) pair, displays a strong inverse temperature dependence, whereas the energy of the band remains nearly constant.
© 2015 by Walter de Gruyter Berlin/Boston
Artikel in diesem Heft
- Evidence for magmatic vapor deposition of anhydrite prior to the 1991 climactic eruption of Mount Pinatubo, Philippines
- Experimental and modeled solubilities of chlorine in aluminosilicate melts, consequences of magma evolution, and implications for exsolution of hydrous chloride melt at Mt. Somma-Vesuvius
- Temperature-induced Al -zoning in hornblendes of the Fish Canyon magma, Colorado
- Analytical techniques for volatiles: A case study using intermediate (andesitic) glasses
- Anomalous optical properties of fibrous tremolite, actinolite, and ferro-actinolite
- Protoanthophyllite from three metamorphosed serpentinites
- Synthesis of beryllian sapphirine in the system MgO-BeO-Al2O3-SiO2-H2O and comparison with naturally occurring beryllian sapphirine and khmaralite. Part 1: Experiments, TEM, and XRD
- Intersite distribution of Fe2+ and Mg in the spinel (sensu stricto)–hercynite series by singlecrystal X-ray diffraction
- Structural relationships in (Mn1–xZnx)Mn2O4 (0 ≤ x ≤ 0.26): The “dragging effect” of the tetrahedron on the octahedron
- The grid-work texture of authigenic microcrystalline quartz in siliceous crust-type (SCT) mineralized horizons
- The crystal structure of vicanite-(Ce), a borosilicate showing an unusual (Si3B3O18)15– polyanion
- Submicrometer optical characterization of the grain boundary of optically active Cr3+ doped polycrystalline Al2O3 by near-field spectroscopy
- High-temperature, high-pressure optical spectroscopic study of ferric-iron-bearing tourmaline
- Infrared and Mössbauer study of Brazilian tourmalines from different geological environments
- Isothermal compression of staurolite: A single-crystal study
- Equation of state measurements of chlorite, pyrophyllite, and talc
- Structure change of Ca1–xSrxTiO3 perovskite with composition and pressure
- Mechanism of 2/1- to 3/2-mullite transformation at 1650 °C
- High-pressure deformation mechanism in scolecite: A combined computationalexperimental study
- Far infrared spectra of K+ in dioctahedral and trioctahedral mixed-layer minerals
- Ab initio quantum mechanical modeling of infrared vibrational frequencies of the OH group in dioctahedral phyllosilicates. Part I: Methods, results and comparison to experimental data
- Ab initio quantum mechanical modeling of infrared vibrational frequencies of the OH group in dioctahedral phyllosilicates. Part II: Main physical factors governing the OH vibrations
- On geological interpretations of crystal size distributions: Constant vs. proportionate growth
- Allabogdanite, (Fe,Ni)2P, a new mineral from the Onello meteorite: The occurrence and crystal structure
- Cristobalite inclusions in the Tatahouine achondrite: Implications for shock conditions
- Letters. Natural occurrence of Fe2SiO4 -spinel in the shocked Umbarger L6 chondrite
- Structural refinements of magnesite at very high pressure
Artikel in diesem Heft
- Evidence for magmatic vapor deposition of anhydrite prior to the 1991 climactic eruption of Mount Pinatubo, Philippines
- Experimental and modeled solubilities of chlorine in aluminosilicate melts, consequences of magma evolution, and implications for exsolution of hydrous chloride melt at Mt. Somma-Vesuvius
- Temperature-induced Al -zoning in hornblendes of the Fish Canyon magma, Colorado
- Analytical techniques for volatiles: A case study using intermediate (andesitic) glasses
- Anomalous optical properties of fibrous tremolite, actinolite, and ferro-actinolite
- Protoanthophyllite from three metamorphosed serpentinites
- Synthesis of beryllian sapphirine in the system MgO-BeO-Al2O3-SiO2-H2O and comparison with naturally occurring beryllian sapphirine and khmaralite. Part 1: Experiments, TEM, and XRD
- Intersite distribution of Fe2+ and Mg in the spinel (sensu stricto)–hercynite series by singlecrystal X-ray diffraction
- Structural relationships in (Mn1–xZnx)Mn2O4 (0 ≤ x ≤ 0.26): The “dragging effect” of the tetrahedron on the octahedron
- The grid-work texture of authigenic microcrystalline quartz in siliceous crust-type (SCT) mineralized horizons
- The crystal structure of vicanite-(Ce), a borosilicate showing an unusual (Si3B3O18)15– polyanion
- Submicrometer optical characterization of the grain boundary of optically active Cr3+ doped polycrystalline Al2O3 by near-field spectroscopy
- High-temperature, high-pressure optical spectroscopic study of ferric-iron-bearing tourmaline
- Infrared and Mössbauer study of Brazilian tourmalines from different geological environments
- Isothermal compression of staurolite: A single-crystal study
- Equation of state measurements of chlorite, pyrophyllite, and talc
- Structure change of Ca1–xSrxTiO3 perovskite with composition and pressure
- Mechanism of 2/1- to 3/2-mullite transformation at 1650 °C
- High-pressure deformation mechanism in scolecite: A combined computationalexperimental study
- Far infrared spectra of K+ in dioctahedral and trioctahedral mixed-layer minerals
- Ab initio quantum mechanical modeling of infrared vibrational frequencies of the OH group in dioctahedral phyllosilicates. Part I: Methods, results and comparison to experimental data
- Ab initio quantum mechanical modeling of infrared vibrational frequencies of the OH group in dioctahedral phyllosilicates. Part II: Main physical factors governing the OH vibrations
- On geological interpretations of crystal size distributions: Constant vs. proportionate growth
- Allabogdanite, (Fe,Ni)2P, a new mineral from the Onello meteorite: The occurrence and crystal structure
- Cristobalite inclusions in the Tatahouine achondrite: Implications for shock conditions
- Letters. Natural occurrence of Fe2SiO4 -spinel in the shocked Umbarger L6 chondrite
- Structural refinements of magnesite at very high pressure