scholarly journals Theoretical study of metal composite based on pyrolyzed polyacrylonitrile monolayer containing Fe-Co, Ni-Co and Fe-Ni metal atom pairs and silicon amorphizing admixture

2020 ◽  
Vol 6 (3) ◽  
pp. 95-99
Author(s):  
Irina V. Zaporotskova ◽  
Daniel P. Radchenko ◽  
Lev V. Kozhitov ◽  
Pavel A. Zaporotskov ◽  
Alena V. Popkova
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Matrix Material ◽  
Wide Band ◽  
Dft Method ◽  
Metal Composite ◽  
Composite Systems ◽  
Metal Atoms ◽  
Transition Metal Atoms ◽  
Designed Materials

An urgent problem of radio engineering and radioelectronics nowadays is the synthesis of composite materials with preset parameters that can be used as electronics engineering materials. Of special interest are MW range wide-band electromagnetic radiation absorbers. Special attention is paid to materials on the basis of ferromagnetic metals that are capable of effectively absorbing and reflecting incident waves and having a clear nanostructure. Development of nanocapsulated metals will allow controlling the parameters of newly designed materials. This is achieved with the use of polymer matrices, e.g. pyrolyzed polyacrylonitrile (PPAN). This work is a theoretical study of a PPAN monolayer model containing pairs of transition metal atoms iron, nickel and cobalt which possess ferromagnetic properties, in Fe-Co, Ni-Co and Fe-Ni combinations, with silicon amorphizing admixture. We studied the geometrical structure of the metal composite systems which are modeled as PPAN molecular clusters the centers of which are voided of six matrix material atoms, the resultant defects (the so-called pores) being filled with pairs of the metal atoms being studied. The metal containing monolayer proved to be distorted in comparison with the initially planar PPAN monolayer. We plotted single-electron spectra of the composite nanosystems and characterized their band gaps. The presence of metal atoms reduces the band gap of a metal composite as compared with pure PPAN. We determined the charges of the metals and found electron density transfer from metal atoms to their adjacent PPAN monolayer atoms. We calculated the average bond energy of the test metal composite systems and proved them to be stable. The studies involved the use of the density functional theory (DFT) method with the B3LYP functional and the 6-31G(d) basis.

scholarly journals Theoretical studies of a metal composite based on a monolayer of pyrolyzed polyacrylonitrile containing paired metal atoms Cu—Co, Ni—Co, Ni—Cu, Ni—Fe and an amorphizing silicon additive

2020 ◽  
Vol 23 (3) ◽  
pp. 196-202
Author(s):  
I. V. Zaporotskova ◽  
D. P. Radchenko ◽  
L. V. Kozitov ◽  
P. A. Zaporotskov ◽  
A. V. Popkova
Keyword(s):  
Density Functional ◽  
Matrix Material ◽  
Wide Band ◽  
Dft Method ◽  
Metal Composite ◽  
Composite Systems ◽  
Metal Atoms ◽  
Transition Metal Atoms ◽  
Designed Materials ◽  
Incident Waves

An urgent problem of radio engineering and radioelectronics nowadays is the synthesis of composite materials with preset parameters that can be used as electronics engineering materials. Of special interest are MW range wide-band electromagnetic radiation absorbers. Special attention is paid to materials on the basis of ferromagnetic metals that are capable of effectively absorbing and reflecting incident waves and having a clear nanostructure. Development of nanocapsulated metals will allow controlling the parameters of newly designed materials. This is achieved with the use of polymer matrices, e.g. pyrolyzed polyacrylonitrile (PPAN). This work is a theoretical study of a PPAN monolayer model containing pairs of transition metal atoms iron, nickel and cobalt which possess ferromagnetic properties, in Fe–Co, Ni–Co and Fe–Ni combinations, with silicon amorphizing admixture. We studied the geometrical structure of the metal composite systems which are modeled as PPAN molecular clusters the centers of which are voided of six matrix material atoms, the resultant defects (the so-called pores) being filled with pairs of the metal atoms being studied. The metal containing monolayer proved to be distorted in comparison with the initially planar PPAN monolayer. We plotted single-electron spectra of the composite nanosystems and characterized their band gaps. The presence of metal atoms reduces the band gap of a metal composite as compared with pure PPAN. We determined the charges of the metals and found electron density transfer from metal atoms to their adjacent PPAN monolayer atoms. We calculated the average bond energy of the test metal composite systems and proved them to be stable. The studies involved the use of the density functional theory (DFT) method with the B3LYP functional and the 6-31G(d) basis.

STRUCTURES, ELECTRONIC AND MAGNETIC PROPERTIES OF C20 FULLERENES DOPED TRANSITION METAL ATOMS M@C20 (M = Fe, Co, Ti, V)

2010 ◽  
Vol 21 (12) ◽  
pp. 1469-1477 ◽  
Author(s):  
M. SAMAH ◽  
B. BOUGHIDEN
Keyword(s):  
Density Functional Theory ◽  
Magnetic Moment ◽  
Density Functional ◽  
Binding Energies ◽  
Functional Theory ◽  
Magnetic Dipoles ◽  
Metal Atoms ◽  
Transition Metal Atoms ◽  
Semiconductor Behavior ◽  
Co Doped

Structures, binding energies, magnetic and electronic properties endohedrally doped C 20 fullerenes by metallic atoms ( Fe , Co , Ti and V ) have been obtained by pseudopotential density functional theory. All M @ C 20, except Co @ C 20, are more stable than the undoped C 20 cage. The magnetic moment values are 1 and 2μB. These values and semiconductor behavior give to these compounds interesting feature in several technological applications. Titanium doped C 20 has a same magnetic moment than the isolated Ti atom. Hybridization process in the Co doped C 20 fullerene is most strong than in other doped cages. Electrical and magnetic dipoles calculated in the iron doped C 20 are very strong compared with other clusters.

Theoretical Study of Si-Rich Transition-Metal Silicides with Double-Graphene-Like Structures

2006 ◽  
Vol 958 ◽  
Author(s):  
Takehide Miyazaki ◽  
Toshihiko Kanayama
Keyword(s):  
Transition Metal ◽  
Theoretical Study ◽  
Layer Structure ◽  
Geometry Optimization ◽  
Energy Calculation ◽  
Total Energy Calculation ◽  
Metal Atoms ◽  
Transition Metal Atoms ◽  
Metal Silicides ◽  
Potential Impact

ABSTRACTWe propose a novel form of graphene-like Si nanostructure based on ab initio total-energy calculation and geometry optimization, (MSi12)n, with M being transition metal atom. It has a three-layer structure, where the two layers of Si atoms in graphene-like positions sandwich another layer of transition metal atoms. The electronic structure may become semiconducting or metallic, depending on the choice of M and arrangement of Si atoms. This hypothetical material can be regarded as a Si-rich phase of transition metal silicide. A potential impact of our finding in forthcoming ultra-scaled Si technology is also discussed.

A DENSITY-FUNCTIONAL-THEORY STUDY OF MAGNETIC ANISOTROPIES OF ONE-DIMENSIONAL Ni CHAINS AND MAGNETISM OF 3D TRANSITION METALS ON Au(110)-(1 × 2) SURFACE

2008 ◽  
Vol 15 (05) ◽  
pp. 567-579 ◽  
Author(s):  
WEI FAN ◽  
XIN-GAO GONG
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Density Functional ◽  
Functional Theory ◽  
Direction Parallel ◽  
Metal Atoms ◽  
Transition Metal Atoms ◽  
The Density Functional Theory ◽  
Atomic Chains ◽  
Supported Ni

Based on the Density Functional Theory (DFT) with noncollinear-magnetism formulations, we have calculated the magnetism of single 3d transition-metal atoms and the magnetic anisotropies of supported Ni chains on the Au(110)-(1 × 2) surface. Our results for single absorbed 3d transition-metal atoms show that the surface relaxations enhance the orbital moments of left-end elements (Ti, V) and quenches the orbital moments of right-end elements (Fe, Co, Ni) on the Au(110)-(1 × 2) surface. The magnetic anisotropies of Ni atomic chains on the surface are closely related to orbital quenching. The easy magnetized axes change from the direction parallel to the chains to the direction perpendicular to the Ni chains when they absorb on the surface.

A one-dimensional copper(II) coordination polymer incorporating succinate and N,N-diethylethylenediamine ligands: crystallographic analysis, vibrational and surface features, and DFT analysis

2017 ◽  
Vol 73 (7) ◽  
pp. 517-524 ◽  
Author(s):  
Fatih Şen ◽  
Sevgi Kansiz ◽  
İbrahim Uçar
Keyword(s):  
Density Functional ◽  
Crystallographic Analysis ◽  
Basic Solution ◽  
Functional Theory ◽  
Coordination Environment ◽  
One Dimensional ◽  
Metal Atoms ◽  
Transition Metal Atoms ◽  
Square Planar ◽  
Polymeric Chains

Transition metal atoms can be bridged by aliphatic dicarboxylate ligands to produce chains, layers and frameworks. The reaction of copper sulfate with succinic acid (H2succ) and N,N-diethylethylenediamine (deed) in basic solution produces the complex catena-poly[[[(N,N-diethylethylenediamine-κ2 N,N′)copper(II)]-μ-succinato-κ2 O 1:O 4] tetrahydrate], {[Cu(C4H4O4)(C6H16N2)]·4H2O} n or {[Cu(succ)(deed)]·4H2O} n . Each carboxylate group of the succinate ligand coordinates to a CuII atom in a monodentate fashion, giving rise to a square-planar coordination environment. The succinate ligands bridge the CuII centres to form one-dimensional polymeric chains. Hydrogen bonds between the ligands and water molecules link these chains into sheets that lie in the ab plane. Density functional theory (DFT) calculations were used to support the experimental data. From these calculations, a good linear correlation was observed between the experimental and theoretically predicted structural and spectroscopic parameters (R 2 ∼ 0.97).

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