Exploring the stability and reactivity of Ni2P and Mo2C catalysts using ab initio atomistic thermodynamics and conceptual DFT approaches

2017 ◽  
Vol 7 (3) ◽  
pp. 377-383 ◽  
Author(s):  
Ángel Morales-García ◽  
Junjie He ◽  
Pengbo Lyu ◽  
Petr Nachtigall
Keyword(s):  
Ab Initio ◽  
Conceptual Dft ◽  
Atomistic Thermodynamics ◽  
The Stability

Insights on the stability of cuprous chloride under high pressure: An equilibrium ab initio atomistic thermodynamics study

2020 ◽  
Vol 136 ◽  
pp. 109158
Author(s):  
Ibrahim A. Suleiman ◽  
Ahmad T. Shawaqfeh ◽  
Michael Stockenhuber ◽  
Eric M. Kennedy
Keyword(s):  
High Pressure ◽  
Ab Initio ◽  
Cuprous Chloride ◽  
Atomistic Thermodynamics ◽  
The Stability

Stability of Adsorbed Water on TiO2-TiN Interfaces. A First Principles and Ab Initio Thermodynamics Investigation.

2018 ◽  
Author(s):  
Michael Nolan ◽  
Julio Gutierrez ◽  
Pierre Loverra ◽  
Marco Fronzi ◽  
Alan O'Riordan
Keyword(s):  
Ab Initio ◽  
Density Functional ◽  
Adsorbed Water ◽  
Free Energy Calculations ◽  
Ambient Conditions ◽  
High Concentration ◽  
High Coverage ◽  
Reducing Conditions ◽  
Atomistic Thermodynamics ◽  
The Stability

Titanium Nitride (TiN) surfaces can oxidise and the growth of a TiO<sub>x</sub> layer on the surface along with the likely presence of water in the surrounding environment can modify the properties of this widely used coating material. The present Density Functional Theory study, including Hubbard +U correction (DFT+U), investigates the stability of adsorbed water at TiO<sub>2</sub>-TiN interfaces with different defects, that serve as a model for an oxide layer grown on a TiN surface. Surface free energy calculations show the stability of perfect TiN-TiO<sub>2</sub> interface at regular O pressures, while oxygen vacancy-rich TiO<sub>1.88</sub>–TiN is more favourable at reducing conditions. An isolated water is preferentially adsorbed dissociatively at perfect and oxygen defective interfaces while molecular adsorption is more stable at higher coverages. The adsorption energy is stronger at the oxygen defective interfaces which arises from the high concentration of reduced Ti<sup>3+</sup> and strong interfacial atomic relaxations. Ab initio atomistic thermodynamics show that water will be present at high coverage on TiO<sub>2</sub>-TiN interfaces at ambient conditions and the pristine interface is only stable at very low pressure of O and H<sub>2</sub>O. The results of these DFT+U simulations are important for the fundamental understanding of wettability of interfacial systems involving metal oxides.

Stability of Adsorbed Water on TiO2-TiN Interfaces. A First Principles and Ab Initio Thermodynamics Investigation.

2018 ◽  
Author(s):  
Michael Nolan ◽  
Julio Gutierrez ◽  
Pierre Loverra ◽  
Marco Fronzi ◽  
Alan O'Riordan
Keyword(s):  
Ab Initio ◽  
Density Functional ◽  
Adsorbed Water ◽  
Free Energy Calculations ◽  
Ambient Conditions ◽  
High Concentration ◽  
High Coverage ◽  
Reducing Conditions ◽  
Atomistic Thermodynamics ◽  
The Stability

Titanium Nitride (TiN) surfaces can oxidise and the growth of a TiO<sub>x</sub> layer on the surface along with the likely presence of water in the surrounding environment can modify the properties of this widely used coating material. The present Density Functional Theory study, including Hubbard +U correction (DFT+U), investigates the stability of adsorbed water at TiO<sub>2</sub>-TiN interfaces with different defects, that serve as a model for an oxide layer grown on a TiN surface. Surface free energy calculations show the stability of perfect TiN-TiO<sub>2</sub> interface at regular O pressures, while oxygen vacancy-rich TiO<sub>1.88</sub>–TiN is more favourable at reducing conditions. An isolated water is preferentially adsorbed dissociatively at perfect and oxygen defective interfaces while molecular adsorption is more stable at higher coverages. The adsorption energy is stronger at the oxygen defective interfaces which arises from the high concentration of reduced Ti<sup>3+</sup> and strong interfacial atomic relaxations. Ab initio atomistic thermodynamics show that water will be present at high coverage on TiO<sub>2</sub>-TiN interfaces at ambient conditions and the pristine interface is only stable at very low pressure of O and H<sub>2</sub>O. The results of these DFT+U simulations are important for the fundamental understanding of wettability of interfacial systems involving metal oxides.

Ab Initio Study of the Stability of the Ylide-like Intermediate Methyleneoxonium in the Reaction between Singlet Methylene and Water

1996 ◽  
Vol 118 (23) ◽  
pp. 5408-5411 ◽  
Author(s):  
Carlos Gonzalez ◽  
Albeiro Restrepo-Cossio ◽  
Manuel Márquez ◽  
Kenneth B. Wiberg
Keyword(s):  
Ab Initio ◽  
Ab Initio Study ◽  
The Stability ◽  
Singlet Methylene

On the stability of the cuboid singlet (S2)4 supermolecule: Benchmark ab initio studies

2013 ◽  
Vol 138 (9) ◽  
pp. 094317 ◽  
Author(s):  
A. J. Ochoa-Calle ◽  
R. Hernández-Lamoneda ◽  
A. Ramírez-Solís
Keyword(s):  
Ab Initio ◽  
The Stability

scholarly journals Ab Initio Molecular Dynamics Investigations of the Speciation and Reactivity of Deep Eutectic Electrolytes in Aluminum Batteries

2021 ◽  
Author(s):  
David Carrasco-Busturia ◽  
Steen Lysgaard ◽  
Piotr Jankowski ◽  
Tejs Vegge ◽  
Arghya Bhowmik ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Ab Initio ◽  
Deep Eutectic Solvents ◽  
Ionic Species ◽  
Electrochemical Activity ◽  
Molecular Composition ◽  
Ab Initio Molecular Dynamics ◽  
The Stability ◽  
Shed Light ◽  
Battery Anode

Deep eutectic solvents (DES) have emerged as an alternative for conventional ionic<br>liquids in aluminum batteries. Elucidating DES composition is fundamental to<br>understand aluminum electrodeposition in the battery anode. Despite numerous<br>experiemental efforts, the speciation of these DES remains elusive. This work shows<br>how \textit{Ab initio} molecular dynamics (AIMD) simulations can shed light on the<br>molecular composition of DES. For the particular example of AlCl$_{3}$:urea, one of<br>the most popular DES, we carried out a systematic AIMD study, showing how an<br>excess of AlCl$_{3}$ in the AlCl$_{3}$:urea mixture promotes the stability of ionic<br>species vs neutral ones and also favors the reactivity in the system. These two facts<br>explain the experimentally observed enhanced electrochemical activity in salt-rich<br>DES. We also observe the transfer of simple $[$AlCl$_{x}$(urea)$_{y}]$ clusters<br>between different species in the liquid, giving rise to free $[$AlCl$_{4}]^{-}$ units. The<br>small size of these $[$AlCl$_{4}]^{-}$ units favors the transport of ionic species towards<br>the anode, facilitating the electrodeposition of aluminum.

scholarly journals Quantum Mechanical-Based Stability Evaluation of Crystal Structures for HIV-Targeted Drug Cabotegravir

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7178
Author(s):  
Yanqiang Han ◽  
Hongyuan Luo ◽  
Qianqian Lu ◽  
Zeying Liu ◽  
Jinyun Liu ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Ab Initio ◽  
Crystal Structures ◽  
Structure Prediction ◽  
Hiv Infections ◽  
Integrase Inhibitor ◽  
Hiv Integrase ◽  
Stability Evaluation ◽  
The Stability ◽  
Long Acting

The long-acting parenteral formulation of the HIV integrase inhibitor cabotegravir (GSK744) is currently being developed to prevent HIV infections, benefiting from infrequent dosing and high efficacy. The crystal structure can affect the bioavailability and efficacy of cabotegravir. However, the stability determination of crystal structures of GSK744 have remained a challenge. Here, we introduced an ab initio protocol to determine the stability of the crystal structures of pharmaceutical molecules, which were obtained from crystal structure prediction process starting from the molecular diagram. Using GSK744 as a case study, the ab initio predicted that Gibbs free energy provides reliable further refinement of the predicted crystal structures and presents its capability for becoming a crystal stability determination approach in the future. The proposed work can assist in the comprehensive screening of pharmaceutical design and can provide structural predictions and stability evaluation for pharmaceutical crystals.

scholarly journals Ab initio thermodynamics of liquid and solid water

2019 ◽  
Vol 116 (4) ◽  
pp. 1110-1115 ◽  
Author(s):  
Bingqing Cheng ◽  
Edgar A. Engel ◽  
Jörg Behler ◽  
Christoph Dellago ◽  
Michele Ceriotti
Keyword(s):  
Machine Learning ◽  
Thermodynamic Properties ◽  
Ab Initio ◽  
Density Functional ◽  
Machine Learning Techniques ◽  
Intermediate Step ◽  
Hybrid Functional ◽  
Learning Techniques ◽  
The Stability ◽  
Comprehensive Framework

Thermodynamic properties of liquid water as well as hexagonal (Ih) and cubic (Ic) ice are predicted based on density functional theory at the hybrid-functional level, rigorously taking into account quantum nuclear motion, anharmonic fluctuations, and proton disorder. This is made possible by combining advanced free-energy methods and state-of-the-art machine-learning techniques. The ab initio description leads to structural properties in excellent agreement with experiments and reliable estimates of the melting points of light and heavy water. We observe that nuclear-quantum effects contribute a crucial 0.2 meV/H2O to the stability of ice Ih, making it more stable than ice Ic. Our computational approach is general and transferable, providing a comprehensive framework for quantitative predictions of ab initio thermodynamic properties using machine-learning potentials as an intermediate step.

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