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.

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.

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 Towards crystal structure prediction of complex organic compounds – a report on the fifth blind test

2011 ◽  
Vol 67 (6) ◽  
pp. 535-551 ◽  
Author(s):  
David A. Bardwell ◽  
Claire S. Adjiman ◽  
Yelena A. Arnautova ◽  
Ekaterina Bartashevich ◽  
Stephan X. M. Boerrigter ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Structure Prediction ◽  
Density Functional ◽  
Crystal Structure Prediction ◽  
Blind Test ◽  
Functional Theory ◽  
Flexible Molecule ◽  
Successful Prediction ◽  
The Many ◽  
Complex Organic

Following on from the success of the previous crystal structure prediction blind tests (CSP1999, CSP2001, CSP2004 and CSP2007), a fifth such collaborative project (CSP2010) was organized at the Cambridge Crystallographic Data Centre. A range of methodologies was used by the participating groups in order to evaluate the ability of the current computational methods to predict the crystal structures of the six organic molecules chosen as targets for this blind test. The first four targets, two rigid molecules, one semi-flexible molecule and a 1:1 salt, matched the criteria for the targets from CSP2007, while the last two targets belonged to two new challenging categories – a larger, much more flexible molecule and a hydrate with more than one polymorph. Each group submitted three predictions for each target it attempted. There was at least one successful prediction for each target, and two groups were able to successfully predict the structure of the large flexible molecule as their first place submission. The results show that while not as many groups successfully predicted the structures of the three smallest molecules as in CSP2007, there is now evidence that methodologies such as dispersion-corrected density functional theory (DFT-D) are able to reliably do so. The results also highlight the many challenges posed by more complex systems and show that there are still issues to be overcome.

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 Density functional theory in the solid state

2014 ◽  
Vol 372 (2011) ◽  
pp. 20130270 ◽  
Author(s):  
Philip J. Hasnip ◽  
Keith Refson ◽  
Matt I. J. Probert ◽  
Jonathan R. Yates ◽  
Stewart J. Clark ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Density Functional Theory ◽  
Solid State ◽  
Structure Prediction ◽  
Density Functional ◽  
Materials Science ◽  
Difficult Problem ◽  
Structure Property ◽  
Defect States ◽  
Functional Theory

Density functional theory (DFT) has been used in many fields of the physical sciences, but none so successfully as in the solid state. From its origins in condensed matter physics, it has expanded into materials science, high-pressure physics and mineralogy, solid-state chemistry and more, powering entire computational subdisciplines. Modern DFT simulation codes can calculate a vast range of structural, chemical, optical, spectroscopic, elastic, vibrational and thermodynamic phenomena. The ability to predict structure–property relationships has revolutionized experimental fields, such as vibrational and solid-state NMR spectroscopy, where it is the primary method to analyse and interpret experimental spectra. In semiconductor physics, great progress has been made in the electronic structure of bulk and defect states despite the severe challenges presented by the description of excited states. Studies are no longer restricted to known crystallographic structures. DFT is increasingly used as an exploratory tool for materials discovery and computational experiments, culminating in ex nihilo crystal structure prediction, which addresses the long-standing difficult problem of how to predict crystal structure polymorphs from nothing but a specified chemical composition. We present an overview of the capabilities of solid-state DFT simulations in all of these topics, illustrated with recent examples using the CASTEP computer program.

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>

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