Distinguishing the close-packed hexagonal and face centered cubic phases of the metallization of diamond by polarization-dependent extended x-ray absorption fine structure

Author(s):  
K. M. Kemner
2011 ◽  
Vol 40 (8) ◽  
pp. 1007-1012
Author(s):  
Alex Perálvarez-Marín ◽  
Francesc Sepulcre ◽  
Mercedes Márquez ◽  
Maria Grazia Proietti ◽  
Esteve Padrós

2021 ◽  
Vol 4 (10) ◽  
pp. 5-10
Author(s):  
Ba Duc Nguyen ◽  
Quang Tho Vu ◽  
Phi Hiep Trinh ◽  
Quynh Lam Nguyen Thi

The effects of the doping ratio and temperature on the cumulants andthermodynamic parameters of crystal structure metals and their alloys wasinvestigated using the anharmonic correlated Einstein model, in extended X-ray absorption fine structure (EXAFS) spectra. We derived analytical expressions for the EXAFS cumulants, correlated Einstein frequency, Einstein temperature, and effective spring constant. We have considered parameters of the effective Morsepotential and the Debye-Waller factor depend on temperature and the effects of the doping ratio of face-centered-cubic (fcc) crystals of copper (Cu-Cu), silver (Ag-Ag), and hexagonal-close-packed (hcp) crystal of zinc (Zn-Zn), and their alloys of Cu-Ag and Cu-Zn. The derived anharmonic effective potential includes the contributions of all the nearest neighbors of the absorbing and scattering atoms. This accounts for three-dimensional interactions and the parameters of theMorse potential, to describe single-pair atomic interactions. The numericalresults of the EXAFS cumulants, thermodynamic parameters, and anharmonic effective potential agree reasonably with experiments and other theories.


2000 ◽  
Vol 454-456 ◽  
pp. 723-728 ◽  
Author(s):  
H. Magnan ◽  
P. Le Fèvre ◽  
A. Midoir ◽  
D. Chandesris ◽  
H. Jaffrès ◽  
...  

Author(s):  
Kazumasa Murata ◽  
Junya Ohyama ◽  
Atsushi Satsuma

In the present study, the redispersion behavior of Ag particles on ZSM-5 in the presence of coke was observed using in situ X-ray absorption fine structure (XAFS) spectroscopy.


2021 ◽  
Author(s):  
Gregory M. Su ◽  
Han Wang ◽  
Brandon R. Barnett ◽  
Jeffrey R. Long ◽  
David Prendergast ◽  
...  

In situ near edge X-ray absorption fine structure spectroscopy directly probes unoccupied states associated with backbonding interactions between the open metal site in a metal–organic framework and various small molecule guests.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Hiroyuki Ikemoto ◽  
Takafumi Miyanaga

AbstractIn this review, we make a survey of the structure studies for the chalcogen elements and several chalcogenides in liquid, amorphous and nanosized state by using X-ray absorption fine structure (XAFS). The chalcogen elements have hierarchic structures; the chain structure constructed with the strong covalent bond as a primary structure, and the weaker interaction between chains as a secondary one. Existence of these two kinds of interactions induces exotic behaviors in the liquid, amorphous and nanosized state of the chalcogen and chalcogenides. XAFS is a powerful structure analysis technique for multi-element systems and the disordered materials, so it is suitable for the study of such as liquid, amorphous and nanosized mixtures. In section 2, the structures for the liquid state are discussed, which show the interesting semiconductor-metal transition depending on their temperatures and components. In section 3, the structure for the amorphous states are discussed. Especially, some of chalcogens and chalcogenides present the photostructural change, which is important industrial application. In section 4, the structures of nanosized state, nanoparticles and isolated chain confined into the narrow channel, are discussed. The studies of the nanoparticle and the isolated chain reveal the alternative role between the intrachain covalent bonds and the interchain interaction.


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