scholarly journals First principles hybrid Hartree-Fock-DFT calculations of bulk and (001) surface F centers in oxide perovskites and alkaline-earth fluorides

2020 ◽  
Vol 46 (12) ◽  
pp. 1206-1212
Author(s):  
R. Eglitis ◽  
A. I. Popov ◽  
J. Purans ◽  
Ran Jia
Keyword(s):  
Dft Calculations ◽  
First Principles ◽  
Alkaline Earth ◽  
Hartree Fock ◽  
F Centers

scholarly journals First-principles and semiempirical Hartree-Fock calculations for F centers in KNbO[sub 3] and Li impurities in KTaO[sub 3]

1998 ◽  
Author(s):  
R. I. Eglitis ◽  
E. A. Kotomin ◽  
A. V. Postnikov ◽  
N. E. Christensen ◽  
G. Borstel
Keyword(s):  
First Principles ◽  
Hartree Fock ◽  
F Centers

Alkaline earth ion exchange study of pure silica LTA zeolites using periodic first-principles calculations

2019 ◽  
Vol 43 (43) ◽  
pp. 16835-16840
Author(s):  
Vancho Kocevski ◽  
Shenyang Y. Hu ◽  
Theodore M. Besmann
Keyword(s):  
Ion Exchange ◽  
Dft Calculations ◽  
First Principles ◽  
Alkaline Earth ◽  
Type A ◽  
First Principles Calculations ◽  
Pure Silica ◽  
Exchange Study ◽  
Lta Zeolite

The Linde Type A (LTA) zeolite capability to exchange alkaline earth ions is analyzed using DFT calculations, considering the systems to be in water and vacuum, investigating the LTA's potential as a material for radioactive decontamination processes.

scholarly journals Comparative Hybrid Hartree-Fock-DFT Calculations of WO2-Terminated Cubic WO3 as Well as SrTiO3, BaTiO3, PbTiO3 and CaTiO3 (001) Surfaces

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 455
Author(s):  
R. I. Eglitis ◽  
Juris Purans ◽  
Ran Jia
Keyword(s):  
Dft Calculations ◽  
Chemical Bond ◽  
First Principles ◽  
Band Gaps ◽  
First Principles Calculations ◽  
Surface Band ◽  
Hartree Fock ◽  
Bond Population ◽  
Bulk Band ◽  
Crystal Bulk

We performed, to the best of our knowledge, the world’s first first-principles calculations for the WO2-terminated cubic WO3 (001) surface and analyzed the systematic trends in the WO3, SrTiO3, BaTiO3, PbTiO3 and CaTiO3 (001) surface ab initio calculations. According to our first principles calculations, all WO2 or TiO2-terminated WO3, SrTiO3, BaTiO3, PbTiO3 and CaZrO3 (001) surface upper-layer atoms relax inwards towards the crystal bulk, while all second-layer atoms relax upwards. The only two exceptions are outward relaxations of first layer WO2 and TiO2-terminated WO3 and PbTiO3 (001) surface O atoms. The WO2 or TiO2-terminated WO3, SrTiO3, BaTiO3, PbTiO3 and CaTiO3 (001) surface-band gaps at the Γ–Γ point are smaller than their respective bulk-band gaps. The Ti–O chemical bond populations in the SrTiO3, BaTiO3, PbTiO3 and CaTiO3 bulk are smaller than those near the TiO2-terminated (001) surfaces. Conversely, the W–O chemical bond population in the WO3 bulk is larger than near the WO2-terminated WO3 (001) surface.

A first-principles study on alkaline earth metal atom substituted monolayer boron nitride (BN)

2017 ◽  
Vol 5 (32) ◽  
pp. 8112-8127 ◽  
Author(s):  
Rafique Muhammad ◽  
Yong Shuai ◽  
He-Ping Tan
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
Boron Nitride ◽  
Dft Calculations ◽  
First Principles ◽  
Density Functional ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Alkaline Earth Metal ◽  
Functional Theory

This paper presents first-principles density functional theory (DFT) calculations for the structural, electronic, magnetic and optical properties of monolayer boron nitride (BN) doped with different alkaline earth metal (AEM) atoms.

A first-principles Hartree-Fock description of MnO at high pressures

1998 ◽  
Vol 77 (4) ◽  
pp. 1063-1075
Author(s):  
W. C. Mackrodt, E.-A. Williamson, D. W
Keyword(s):  
First Principles ◽  
High Pressures ◽  
Hartree Fock

A first-principles study on the electronic and optical properties of a type-II C2N/g-ZnO van der Waals heterostructure

2021 ◽  
Vol 23 (6) ◽  
pp. 3963-3973
Author(s):  
Jianxun Song ◽  
Hua Zheng ◽  
Minxia Liu ◽  
Geng Zhang ◽  
Dongxiong Ling ◽  
...  
Keyword(s):  
Optical Properties ◽  
Dft Calculations ◽  
First Principles ◽  
Van Der Waals ◽  
Band Alignment ◽  
Type Ii ◽  
Electronic And Optical Properties ◽  
Direct Bandgap ◽  
Van Der Waals Heterostructure ◽  
Vdw Heterostructure

The structural, electronic and optical properties of a new vdW heterostructure, C2N/g-ZnO, with an intrinsic type-II band alignment and a direct bandgap of 0.89 eV at the Γ point are extensively studied by DFT calculations.

Interface coupling and charge doping in graphene on ferroelectric BiAlO3(0001) polar surfaces

2021 ◽  
Vol 23 (5) ◽  
pp. 3407-3416
Author(s):  
Jin Yuan ◽  
Jian-Qing Dai ◽  
Cheng Ke ◽  
Zi-Cheng Wei
Keyword(s):  
Dft Calculations ◽  
Hybrid System ◽  
First Principles ◽  
Doping Effect ◽  
Coupling Mechanism ◽  
Polarization Reversal ◽  
Interface Coupling ◽  
Polar Surfaces ◽  
Charge Doping

The interface coupling mechanism, charge doping effect, and effect of polarization reversal in the graphene/BiAlO3(0001) hybrid system are explored by first-principles DFT calculations.

scholarly journals Computational Methods for Ab Initio Molecular Dynamics

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Eric Paquet ◽  
Herna L. Viktor
Keyword(s):  
Molecular Dynamics ◽  
Quantum Mechanics ◽  
Ab Initio ◽  
First Principles ◽  
Density Functional ◽  
Path Integrals ◽  
Ab Initio Molecular Dynamics ◽  
Molecular Systems ◽  
Hartree Fock ◽  
Computational Perspective

Ab initio molecular dynamics is an irreplaceable technique for the realistic simulation of complex molecular systems and processes from first principles. This paper proposes a comprehensive and self-contained review of ab initio molecular dynamics from a computational perspective and from first principles. Quantum mechanics is presented from a molecular dynamics perspective. Various approximations and formulations are proposed, including the Ehrenfest, Born–Oppenheimer, and Hartree–Fock molecular dynamics. Subsequently, the Kohn–Sham formulation of molecular dynamics is introduced as well as the afferent concept of density functional. As a result, Car–Parrinello molecular dynamics is discussed, together with its extension to isothermal and isobaric processes. Car–Parrinello molecular dynamics is then reformulated in terms of path integrals. Finally, some implementation issues are analysed, namely, the pseudopotential, the orbital functional basis, and hybrid molecular dynamics.

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