scholarly journals Stability-Ranking of Crystalline Ice Polymorphs Using Density-Functional Theory

Crystals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 40
Author(s):  
Pralok K. Samanta ◽  
Christian J. Burnham ◽  
Niall J. English
Keyword(s):  
Density Functional Theory ◽  
Structure Prediction ◽  
Density Functional ◽  
Applied Pressure ◽  
External Pressure ◽  
Crystal Structure Prediction ◽  
Functional Theory ◽  
Stability Ranking ◽  
High Level ◽  
Basin Hopping

In this work, we consider low-enthalpy polymorphs of ice, predicted previously using a modified basin-hopping algorithm for crystal-structure prediction with the TIP4P empirical potential at three pressures (0, 4 and 8 kbar). We compare and (re)-rank the reported ice polymorphs in order of energetic stability, using high-level quantum-chemical calculations, primarily in the guise of sophisticated Density-Functional Theory (DFT) approaches. In the absence of applied pressure, ice Ih is predicted to be energetically more stable than ice Ic, and TIP4P-predicted results and ranking compare well with the results obtained from DFT calculations. However, perhaps not unexpectedly, the deviation between TIP4P- and DFT-calculated results increases with applied external pressure.

scholarly journals Phase relations, and mechanical and electronic properties of nickel borides, carbides, and nitrides from ab initio calculations

RSC Advances ◽  
2021 ◽  
Vol 11 (53) ◽  
pp. 33781-33787
Author(s):  
Nursultan E. Sagatov ◽  
Aisulu U. Abuova ◽  
Dinara N. Sagatova ◽  
Pavel N. Gavryushkin ◽  
Fatima U. Abuova ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Density Functional Theory ◽  
Ab Initio Calculations ◽  
Structure Prediction ◽  
Density Functional ◽  
Pressure Range ◽  
Prediction Methods ◽  
Crystal Structure Prediction ◽  
Functional Theory ◽  
C And N

Based on density functional theory and the crystal structure prediction methods, USPEX and AIRSS, stable intermediate compounds in the Ni–X (X = B, C, and N) systems and their structures were determined in the pressure range of 0–400 GPa.

Fast Treatment of Noncovalent Packing Using Dispersion-Corrected Harris Approximate Density Functional Theory

2017 ◽  
Author(s):  
Andrey B. Sharapov ◽  
Geoffrey Hutchison
Keyword(s):  
Density Functional Theory ◽  
Structure Prediction ◽  
Density Functional ◽  
Materials Science ◽  
Basis Sets ◽  
Yield Potential ◽  
Crystal Structure Prediction ◽  
Functional Theory ◽  
Functional Methods ◽  
Computational Speed

<div> <div> <div> <p>The formation of molecular aggregates and assemblies is an important process across chemistry, biology, and materials science. In applications such as crystal structure prediction, a balance between high accuracy and computational speed is highly desirable. We present a new method for predicting approximate bimolecular potential curves using dispersion-corrected Harris approximate-density functional theory and an improved estimate of the bimolecular electron density. Our results on benzene dimer and thiophene dimer yield potential energy curves within a few percent of MP2 theory and a speedup of ~10x over conventional density functional methods. The code is highly parallel and gives greater speedups on larger systems and basis sets. </p> </div> </div> </div>

scholarly journals Prediction of unexpected BnPn structures: promising materials for non-linear optical devices and photocatalytic activities

2021 ◽  
Author(s):  
Zabiollah Mahdavifar
Keyword(s):  
Crystal Structure ◽  
Density Functional Theory ◽  
Structure Prediction ◽  
Density Functional ◽  
Modern Method ◽  
Optical Devices ◽  
Crystal Structure Prediction ◽  
Functional Theory ◽  
Photocatalytic Activities ◽  
Stable Structures

In the present work, a modern method of crystal structure prediction, namely USPEX conjugated with density functional theory (DFT) calculations, was used to predict the new stable structures of BnPn (n = 12, 24) clusters.

Fast Treatment of Noncovalent Packing Using Dispersion-Corrected Harris Approximate Density Functional Theory

2017 ◽  
Author(s):  
Andrey B. Sharapov ◽  
Geoffrey Hutchison
Keyword(s):  
Density Functional Theory ◽  
Structure Prediction ◽  
Density Functional ◽  
Materials Science ◽  
Basis Sets ◽  
Yield Potential ◽  
Crystal Structure Prediction ◽  
Functional Theory ◽  
Functional Methods ◽  
Computational Speed

<div> <div> <div> <p>The formation of molecular aggregates and assemblies is an important process across chemistry, biology, and materials science. In applications such as crystal structure prediction, a balance between high accuracy and computational speed is highly desirable. We present a new method for predicting approximate bimolecular potential curves using dispersion-corrected Harris approximate-density functional theory and an improved estimate of the bimolecular electron density. Our results on benzene dimer and thiophene dimer yield potential energy curves within a few percent of MP2 theory and a speedup of ~10x over conventional density functional methods. The code is highly parallel and gives greater speedups on larger systems and basis sets. </p> </div> </div> </div>

scholarly journals Overcoming the difficulties of predicting conformational polymorph energetics in molecular crystals via correlated wavefunction methods

2020 ◽  
Vol 11 (8) ◽  
pp. 2200-2214 ◽  
Author(s):  
Chandler Greenwell ◽  
Jessica L. McKinley ◽  
Peiyu Zhang ◽  
Qun Zeng ◽  
Guangxu Sun ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Density Functional Theory ◽  
Structure Prediction ◽  
Density Functional ◽  
Prediction Models ◽  
Molecular Crystals ◽  
Crystal Structure Prediction ◽  
Functional Theory ◽  
New Model ◽  
Wavefunction Methods

Widely used crystal structure prediction models based on density functional theory can perform poorly for conformational polymorphs, but a new model corrects those polymorph stability rankings.

scholarly journals A computational study for the reaction mechanism of metal-free cyanomethylation of aryl alkynoates with acetonitrile

RSC Advances ◽  
2021 ◽  
Vol 11 (30) ◽  
pp. 18246-18251
Author(s):  
Selçuk Eşsiz
Keyword(s):  
Density Functional Theory ◽  
Reaction Mechanism ◽  
Density Functional ◽  
Computational Study ◽  
Coupled Cluster ◽  
Functional Theory ◽  
Metal Free ◽  
Coupled Cluster Methods ◽  
High Level ◽  
Cluster Methods

A computational study of metal-free cyanomethylation and cyclization of aryl alkynoates with acetonitrile is carried out employing density functional theory and high-level coupled-cluster methods, such as [CCSD(T)].

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