Amorphous boron carbide from ab initio simulations

2020 ◽  
Vol 173 ◽  
pp. 109397 ◽  
Author(s):  
Tevhide Ayça Yıldız ◽  
Murat Durandurdu
Keyword(s):  
Boron Carbide ◽  
Ab Initio ◽  
Amorphous Boron ◽  
Ab Initio Simulations

scholarly journals Impact scenarios in boron carbide: A computational study

2016 ◽  
Vol 15 (07) ◽  
pp. 1650055 ◽  
Author(s):  
Isaac J. Sugden ◽  
David F. Plant ◽  
Robert G. Bell
Keyword(s):  
Boron Carbide ◽  
Ab Initio ◽  
Lattice Site ◽  
Computational Study ◽  
High Energy ◽  
Ab Initio Simulations ◽  
Energy Impact ◽  
Radiative Impacts ◽  
Interstitial Defects ◽  
Impact Events

The effect of radiative impacts on the structure of boron carbide has been studied by both classical and ab initio simulations. As a part of this study, a new forcefield was developed for use in studying boron carbide materials. Impact scenarios in boron carbide were simulated in order to investigate the exceptional resistance of this material, and other icosahedral boron solids, to high-energy impact events. It was observed that interstitial defects created by radiative impacts are likely to be quenched locally, utilizing the high substitutional disorder of chains and cages in the boron carbide structure, rather than via impacted atoms recombining with their vacated lattice site.

Quantum Mechanical Interpretation of the Ultra-Low Energy Methyl-Rotation Dynamics in Porous Metal-Organic Frameworks Probed by Low-Frequency Vibrational Spectroscopy and ab initio Simulations

2018 ◽  
Author(s):  
Qi Li ◽  
Adam J. Zaczek ◽  
Timothy M. Korter ◽  
J. Axel Zeitler ◽  
Michael T. Ruggiero
Keyword(s):  
Ab Initio ◽  
Metal Organic Frameworks ◽  
Low Frequency ◽  
Rotor Dynamics ◽  
Quantum Mechanical ◽  
Valuable Insight ◽  
Void Space ◽  
Ab Initio Simulations ◽  
Metal Organic ◽  
Insight Into

<div>Understanding the nature of the interatomic interactions present within the pores of metal-organic frameworks</div><div>is critical in order to design and utilize advanced materials</div><div>with desirable applications. In ZIF-8 and its cobalt analogue</div><div>ZIF-67, the imidazolate methyl-groups, which point directly</div><div>into the void space, have been shown to freely rotate - even</div><div>down to cryogenic temperatures. Using a combination of ex-</div><div>perimental terahertz time-domain spectroscopy, low-frequency</div><div>Raman spectroscopy, and state-of-the-art ab initio simulations,</div><div>the methyl-rotor dynamics in ZIF-8 and ZIF-67 are fully charac-</div><div>terized within the context of a quantum-mechanical hindered-</div><div>rotor model. The results lend insight into the fundamental</div><div>origins of the experimentally observed methyl-rotor dynamics,</div><div>and provide valuable insight into the nature of the weak inter-</div><div>actions present within this important class of materials.</div>

scholarly journals Early-stage formation of (hydr)oxo bridges in transition-metal catalysts for photosynthetic processes

2021 ◽  
Author(s):  
Shin Nakamura ◽  
Matteo Capone ◽  
Giuseppe Mattioli ◽  
Leonardo Guidoni
Keyword(s):  
Transition Metal ◽  
Aqueous Solutions ◽  
Ab Initio ◽  
Early Stage ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Electrochemical Potential ◽  
Ab Initio Simulations

Water-oxidizing metal-(hydr)oxo catalyst films can be generally deposited and activated by applying a positive electrochemical potential to suitable starting aqueous solutions. Here, we used ab initio simulations based on density...

scholarly journals The phase diagrams of KCaF3 and NaMgF3 by ab initio simulations

2017 ◽  
Vol 45 (4) ◽  
pp. 311-322 ◽  
Author(s):  
Clément Jakymiw ◽  
Lidunka Vočadlo ◽  
David P. Dobson ◽  
Edward Bailey ◽  
Andrew R. Thomson ◽  
...  
Keyword(s):  
Ab Initio ◽  
Phase Diagrams ◽  
Ab Initio Simulations

Large- Scale ab initio Simulations of Fe-doped SrTiO3 Perovskites

2002 ◽  
Vol 731 ◽  
Author(s):  
R.A. Evarestov ◽  
R.I. Eglitis ◽  
S. Piskunov ◽  
E. A. Kotomin ◽  
G. Borstel
Keyword(s):  
Energy Level ◽  
Ab Initio ◽  
High Spin ◽  
Spin State ◽  
Large Scale ◽  
Covalent Bonding ◽  
Hartree Fock ◽  
Ab Initio Simulations ◽  
Displacement Mode ◽  
Jahn Teller

AbstractUsing the Unrestricted Hartree-Fock method and supercells containing up to 160 atoms, we calculated the energy level positions in the gap and atomic geometry for the Fe4+ impurity substituting for a host Ti atom in SrTiO3. In agreement with experiment, the high spin (S=2) state is much lower in energy than the zero-spin state. The energy level positions strongly depend on the asymmetric displacement mode of the six nearest O ions which is a combination of the Jahn-Teller and breathing modes. A considerable covalent bonding between the Fe ion and four nearest O ions takes place.

Microstructure and deposition mechanism of CVD amorphous boron carbide coatings deposited on SiC substrates at low temperature

2009 ◽  
Vol 35 (5) ◽  
pp. 1877-1882 ◽  
Author(s):  
Bin Zeng ◽  
Zude Feng ◽  
Siwei Li ◽  
Yongsheng Liu ◽  
Laifei Cheng ◽  
...  
Keyword(s):  
Low Temperature ◽  
Boron Carbide ◽  
Amorphous Boron ◽  
Deposition Mechanism ◽  
Carbide Coatings
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