Abstract
Tugtupite [Na8(Al2Be2Si8O24)Cl2] is an extremely ordered mineral containing 27Al, 23Na, and 9Be quadrupolar nuclei. The quadrupolar interaction parameters (QI), Cq and η, for these nuclei were calculated from the electronic structure by full-crystal linearized augmented plane-wave (FC LAPW) or ab initio molecular orbital (MO) calculations. The orientation of the EFG tensors, calculated using FC LAPW correspond with the crystallographic axes a1, a2, and c, and η at the Al site is equal to 0.00 as required by the symmetrical electron density distribution in the a-c planes. The electron density of states (DOS) shows the EFG to originate from the valence band of the p-p, p-s electrons. The agreement between the calculated QI values and experimental results for tugtupite shows that FC LAPW is very effective to evaluate the electronic structure of an ordered mineral, and aid in the interpretation of MAS NMR spectra.
The combination of computational efficiency and accuracy of ab initio cluster MO calculations were examined by using different cluster sizes, basis sets, theoretical levels, and charge backgrounds using the Gaussian 98W program. A small cluster embedded in a point charge background gave sufficiently accurate 27Al EFG tensors, with much greater computational efficiency than with WIEN2k. The MO cluster calculation became closer to the experimental results as the number of atoms in the clusters increased, but the calculation cost increased as well. The point-charge background was found to contribute about 10% to the EFG. MO calculations, with B3LYP level and basis set 6-311G+d** for the cluster of two atom shells around the central Al nucleus, gave quadrupole interaction values within 13% of that found by the FC LAPW method using the WIEN2k program. Therefore, MO cluster calculations can provide a more efficient but less accurate alternative to FC LAPW for quantum calculations of mineral structures.
© 2015 by Walter de Gruyter Berlin/Boston
Artikel in diesem Heft
- Composition and I4/m-P42/n phase transition in scapolite solid solutions
- Synthesis and characterization of K2Ca5(SO4)6·H2O, the equivalent of görgeyite, a rare evaporite mineral
- Phase relations in the system Fe-FeSi at 21 GPa
- The speciation of dissolved H2O in dacitic melt
- Nucleation and growth kinetics of the α-β transformation in Mg2SiO4determined by in situ synchrotron powder X-ray diffraction
- Experimental determination of siderite stability and application to Martian Meteorite ALH84001
- Determination of the molar absorption coefficient for the infrared absorption band of CO2in rhyolitic glasses
- Crystallographic properties of the calcium phosphate mineral, brushite, by means of First Principles calculations
- The crystal structure of jonesite, Ba2(K,Na)[Ti2(Si5Al)O18(H2O)](H2O)n: A first example of titanosilicate with porous double layers
- Crystal-chemistry of talc: A near infrared (NIR) spectroscopy study
- Synthesis of beryllian sapphirine in the system MgO-BeO-Al2O3-SiO2-H2O and comparison with naturally occurring beryllian sapphirine and khmaralite, Part 2: A chemographic study of Be content as a function of P, T, assemblage and FeMg–1exchange
- Spriggite, Pb3[(UO2)6O8(OH)2](H2O)3, a new mineral with β-U3O8–type sheets: Description and crystal structure
- Sieve-textured plagioclase in dacitic magma: Interference imaging results
- Single crystal raman spectroscopy of cerussite
- Sodalite: High-temperature structures obtained from synchrotron radiation and Rietveld refinements
- The structure of metahohmannite, Fe3+2[O(SO4)2]⋅4H2O, by in situ synchrotron powder diffraction
- High-pressure synchrotron X-ray diffraction study of spessartine and uvarovite: A comparison between different equation of state models
- Quantum calculations of the electronic structure and NMR quadrupolar interaction parameters for tugtupite
- Identification of pyrite valence band contributions using synchrotron-excited X-ray photoelectron spectroscopy
- Micro-Raman studies of gypsum in the temperature range between 9 K and 373 K
- A new rare earth disilicate (REE2Si2O7; REE = Dy, Tm, Lu; type-L): Evidence for nonquenchable 10 GPa polymorph with silicon in fivefold trigonal bipyramidal coordination?
- Structural variations in the brownmillerite series Ca2(Fe2–xAlx)O5: Single-crystal X-ray diffraction at 25 °C and high-temperature X-ray powder diffraction (25 °C ≤ T ≤ 1000 °C)
- Peculiarity and defect structure of the natural and synthetic zeolite mordenite: A single-crystal X-ray study
- Model independent phase equilibrium constraints on the ferrosilite activity in the binary Fe-Mg orthopyroxene solid solution
- Microstructural study of synthetic sintered diamond and comparison with carbonado, a natural polycrystalline diamond
- Structural and chemical response to varying [4]B content in zoned Fe-bearing olenite from Koralpe, Austria
- A new dense silica polymorph: A possible link between tetrahedrally and octahedrally coordinated silica
- Epitaxial relationships of clinopyroxene-hosted magnetite determined using electron backscatter diffraction (EBSD) technique
Artikel in diesem Heft
- Composition and I4/m-P42/n phase transition in scapolite solid solutions
- Synthesis and characterization of K2Ca5(SO4)6·H2O, the equivalent of görgeyite, a rare evaporite mineral
- Phase relations in the system Fe-FeSi at 21 GPa
- The speciation of dissolved H2O in dacitic melt
- Nucleation and growth kinetics of the α-β transformation in Mg2SiO4determined by in situ synchrotron powder X-ray diffraction
- Experimental determination of siderite stability and application to Martian Meteorite ALH84001
- Determination of the molar absorption coefficient for the infrared absorption band of CO2in rhyolitic glasses
- Crystallographic properties of the calcium phosphate mineral, brushite, by means of First Principles calculations
- The crystal structure of jonesite, Ba2(K,Na)[Ti2(Si5Al)O18(H2O)](H2O)n: A first example of titanosilicate with porous double layers
- Crystal-chemistry of talc: A near infrared (NIR) spectroscopy study
- Synthesis of beryllian sapphirine in the system MgO-BeO-Al2O3-SiO2-H2O and comparison with naturally occurring beryllian sapphirine and khmaralite, Part 2: A chemographic study of Be content as a function of P, T, assemblage and FeMg–1exchange
- Spriggite, Pb3[(UO2)6O8(OH)2](H2O)3, a new mineral with β-U3O8–type sheets: Description and crystal structure
- Sieve-textured plagioclase in dacitic magma: Interference imaging results
- Single crystal raman spectroscopy of cerussite
- Sodalite: High-temperature structures obtained from synchrotron radiation and Rietveld refinements
- The structure of metahohmannite, Fe3+2[O(SO4)2]⋅4H2O, by in situ synchrotron powder diffraction
- High-pressure synchrotron X-ray diffraction study of spessartine and uvarovite: A comparison between different equation of state models
- Quantum calculations of the electronic structure and NMR quadrupolar interaction parameters for tugtupite
- Identification of pyrite valence band contributions using synchrotron-excited X-ray photoelectron spectroscopy
- Micro-Raman studies of gypsum in the temperature range between 9 K and 373 K
- A new rare earth disilicate (REE2Si2O7; REE = Dy, Tm, Lu; type-L): Evidence for nonquenchable 10 GPa polymorph with silicon in fivefold trigonal bipyramidal coordination?
- Structural variations in the brownmillerite series Ca2(Fe2–xAlx)O5: Single-crystal X-ray diffraction at 25 °C and high-temperature X-ray powder diffraction (25 °C ≤ T ≤ 1000 °C)
- Peculiarity and defect structure of the natural and synthetic zeolite mordenite: A single-crystal X-ray study
- Model independent phase equilibrium constraints on the ferrosilite activity in the binary Fe-Mg orthopyroxene solid solution
- Microstructural study of synthetic sintered diamond and comparison with carbonado, a natural polycrystalline diamond
- Structural and chemical response to varying [4]B content in zoned Fe-bearing olenite from Koralpe, Austria
- A new dense silica polymorph: A possible link between tetrahedrally and octahedrally coordinated silica
- Epitaxial relationships of clinopyroxene-hosted magnetite determined using electron backscatter diffraction (EBSD) technique