Structure and NMR assignment in calcined and as-synthesized forms of AlPO-14: a combined study by first-principles calculations and high-resolution 27Al–31P MAS NMR correlation

2008 ◽  
Vol 10 (37) ◽  
pp. 5754 ◽  
Author(s):  
Sharon E. Ashbrook ◽  
Marica Cutajar ◽  
Chris J. Pickard ◽  
Richard I. Walton ◽  
Stephen Wimperis
Keyword(s):  
High Resolution ◽  
First Principles ◽  
Nmr Assignment ◽  
Mas Nmr ◽  
First Principles Calculations ◽  
31P Mas Nmr

Structure and NMR assignment in AlPO4-15: A combined study by diffraction, MAS NMR and first-principles calculations

2009 ◽  
Vol 11 (5) ◽  
pp. 1001-1006 ◽  
Author(s):  
Peter J. Byrne ◽  
John E. Warren ◽  
Russell E. Morris ◽  
Sharon E. Ashbrook
Keyword(s):  
First Principles ◽  
Nmr Assignment ◽  
Mas Nmr ◽  
First Principles Calculations

First Principles Calculations for Metal/Ceramic Interfaces

1994 ◽  
Vol 357 ◽  
Author(s):  
M. W. Finnis ◽  
C. Kruse ◽  
U. SchÖnberger
Keyword(s):  
Electronic Structure ◽  
High Resolution ◽  
Ab Initio ◽  
First Principles ◽  
Density Functional ◽  
Local Density ◽  
Work Of Adhesion ◽  
First Principles Calculations ◽  
Resolution Electron ◽  
Metal Ceramic

AbstractWe discuss the recent first principles calculations of the properties of interfaces between metals and oxides. This type of calculation is parameter-free, and exploits the density functional theory in the local density approximation to obtain the electronic structure of the system. At the same time the equilibrium atomic structure is sought, which minimises the excess energy of the interface. Up to now calculations of this type have been made for a few model interfaces which are atomically coherent, that is with commensurate lattices. Examples are Ag/MgO and Nb/Al2O3. In these cases it has been possible to predict the structures observed by high resolution electron microscopy. The calculations are actually made in a supercell geometry, in which there are alternating nanolayers of metal and ceramic. Because of the effectiveness of metallic screening in particular, the interfaces between the nanolayers do not interfere much with each other.Besides the electronic structure of the interface, such calculations have provided values of the ideal work of adhesion. Electrostatic image forces in conjunction with the elementary ionic model provide a simple framework for understanding the results.An important role of such calculations is to develop intuition about the nature of the bonding, including the effects of charge transfer, which has formerly only been described in an empirical way. It may then be possible to build atomistic models of the metal/ceramic interaction which have a sound physical basis and can be calibrated against ab initio results. Simpler models are necessary if larger systems, including misfit dislocations and other defects, are to be simulated, with a view to understanding the atomic processes of growth and failure. Another area in which ab initio calculations can be expected to contribute is in the chemistry of impurity segregation and its effect at interfaces. Such theoretical tools are a natural partner to the experimental technique of high resolution electron energy loss spectroscopy for studying the local chemical environment at an interface.

Exploiting the Chemical Shielding Anisotropy to Probe Structure and Disorder in Ceramics: 89Y MAS NMR and First-Principles Calculations

2012 ◽  
Vol 116 (6) ◽  
pp. 4273-4286 ◽  
Author(s):  
Martin R. Mitchell ◽  
Diego Carnevale ◽  
Robin Orr ◽  
Karl R. Whittle ◽  
Sharon E. Ashbrook
Keyword(s):  
First Principles ◽  
Mas Nmr ◽  
First Principles Calculations ◽  
Chemical Shielding

119Sn MAS NMR and first-principles calculations for the investigation of disorder in stannate pyrochlores

2011 ◽  
Vol 13 (2) ◽  
pp. 488-497 ◽  
Author(s):  
Martin R. Mitchell ◽  
Simon W. Reader ◽  
Karen E. Johnston ◽  
Chris J. Pickard ◽  
Karl R. Whittle ◽  
...  
Keyword(s):  
First Principles ◽  
Mas Nmr ◽  
First Principles Calculations

Local environment of arsenic in sulfide minerals: insights from high-resolution X-ray spectroscopies, and first-principles calculations at the As K-edge

2018 ◽  
Vol 33 (12) ◽  
pp. 2070-2082 ◽  
Author(s):  
Le Pape Pierre ◽  
Blanchard Marc ◽  
Juhin Amélie ◽  
Rueff Jean-Pascal ◽  
Ducher Manoj ◽  
...  
Keyword(s):  
High Resolution ◽  
Energy Resolution ◽  
First Principles ◽  
Local Environment ◽  
High Energy ◽  
Sulfide Minerals ◽  
High Energy Resolution ◽  
First Principles Calculations ◽  
X Ray ◽  
X Ray Scattering

To improve our knowledge of arsenic local environment in sulfide minerals, Resonant Inelastic X-Ray Scattering (RIXS) maps and High-Energy Resolution Fluorescence Detected (HERFD) XANES measurements are performed at the As K-edge. In addition, the spectra are compared to XANES modelled through first-principles calculations.

Cation Disorder in Pyrochlore Ceramics: 89Y MAS NMR and First-Principles Calculations

2009 ◽  
Vol 113 (43) ◽  
pp. 18874-18883 ◽  
Author(s):  
Simon W. Reader ◽  
Martin R. Mitchell ◽  
Karen E. Johnston ◽  
Chris J. Pickard ◽  
Karl R. Whittle ◽  
...  
Keyword(s):  
First Principles ◽  
Mas Nmr ◽  
First Principles Calculations ◽  
Cation Disorder
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