Adsorption of Atoms on a Crystalline Ice Surface Model: Results from Periodic ab Initio Simulations

2020 ◽  
pp. 553-560
Author(s):  
Stefano Ferrero ◽  
Berta Martínez-Bachs ◽  
Joan Enrique-Romero ◽  
Albert Rimola
Keyword(s):  
Ab Initio ◽  
Surface Model ◽  
Ab Initio Simulations ◽  
Ice Surface

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

Quantitative structural determination of active sites from in situ and operando XANES spectra: From standard ab initio simulations to chemometric and machine learning approaches

2019 ◽  
Vol 336 ◽  
pp. 3-21 ◽  
Author(s):  
Alexander A. Guda ◽  
Sergey A. Guda ◽  
Kirill A. Lomachenko ◽  
Mikhail A. Soldatov ◽  
Ilia A. Pankin ◽  
...  
Keyword(s):  
Machine Learning ◽  
Ab Initio ◽  
Active Sites ◽  
Structural Determination ◽  
Learning Approaches ◽  
Ab Initio Simulations

scholarly journals A system of conservative regridding for ice–atmosphere coupling in a General Circulation Model (GCM)

2014 ◽  
Vol 7 (3) ◽  
pp. 883-907 ◽  
Author(s):  
R. Fischer ◽  
S. Nowicki ◽  
M. Kelley ◽  
G. A. Schmidt
Keyword(s):  
General Circulation Model ◽  
General Circulation ◽  
Circulation Model ◽  
Grid Cell ◽  
Surface Model ◽  
Ice Flow ◽  
Surface Mass ◽  
Flow Models ◽  
Ice Surface ◽  
Ice Model

Abstract. The method of elevation classes, in which the ice surface model is run at multiple elevations within each grid cell, has proven to be a useful way for a low-resolution atmosphere inside a general circulation model (GCM) to produce high-resolution downscaled surface mass balance fields for use in one-way studies coupling atmospheres and ice flow models. Past uses of elevation classes have failed to conserve mass and energy because the transformation used to regrid to the atmosphere was inconsistent with the transformation used to downscale to the ice model. This would cause problems for two-way coupling. A strategy that resolves this conservation issue has been designed and is presented here. The approach identifies three grids between which data must be regridded and five transformations between those grids required by a typical coupled atmosphere–ice flow model. This paper develops a theoretical framework for the problem and shows how each of these transformations may be achieved in a consistent, conservative manner. These transformations are implemented in Glint2, a library used to couple atmosphere models with ice models. Source code and documentation are available for download. Confounding real-world issues are discussed, including the use of projections for ice modeling, how to handle dynamically changing ice geometry, and modifications required for finite element ice models.

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.

scholarly journals Recently synthesized (Ti1−xMox)2AlC (0 ≤ x ≤ 0.20) solid solutions: deciphering the structural, electronic, mechanical and thermodynamic properties via ab initio simulations

RSC Advances ◽  
2020 ◽  
Vol 10 (52) ◽  
pp. 31535-31546 ◽  
Author(s):  
M. A. Ali ◽  
S. H. Naqib
Keyword(s):  
Density Functional Theory ◽  
Thermodynamic Properties ◽  
Ab Initio ◽  
Solid Solutions ◽  
Density Functional ◽  
Functional Theory ◽  
Ab Initio Simulations

The structural, electronic, mechanical and thermodynamic properties of (Ti1−xMox)2AlC (0 ≤ x ≤ 0.20) were explored using density functional theory.

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