Accurate prediction of second-order elastic constants from first principles: PETN and TATB

2012 ◽  
Author(s):  
Loredana Valenzano ◽  
William J Slough ◽  
Warren Perger
Keyword(s):  
Elastic Constants ◽  
First Principles ◽  
Second Order ◽  
Accurate Prediction

Accurate prediction of Pressure and Temperature T1/2 Variation in Solid State Spin Crossover by Ab Initio Methods: the [CoII(dpzca)2] case

2021 ◽  
Author(s):  
Luca Bondì ◽  
Sally Brooker ◽  
Federico Totti
Keyword(s):  
Solid State ◽  
Ab Initio ◽  
First Principles ◽  
Spin Crossover ◽  
Second Order ◽  
Accurate Prediction ◽  
Ab Initio Methods ◽  
State Spin

Spin crossover (SCO) is among the most complicated second-order transitions to be modelled from first principles; especially solid state SCO with the added complexity of (a) interacting molecules and (b)...

ElaStic: A tool for calculating second-order elastic constants from first principles

2013 ◽  
Vol 184 (8) ◽  
pp. 1861-1873 ◽  
Author(s):  
Rostam Golesorkhtabar ◽  
Pasquale Pavone ◽  
Jürgen Spitaler ◽  
Peter Puschnig ◽  
Claudia Draxl
Keyword(s):  
Elastic Constants ◽  
First Principles ◽  
Second Order

scholarly journals Nonlinear Elasticity of Borocarbide Superconductor YNi2B2C: A First-Principles Study

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Lili Liu ◽  
Cai Chen ◽  
Dingxing Liu ◽  
Zhengquan Hu ◽  
Gang Xu ◽  
...  
Keyword(s):  
High Pressure ◽  
Elastic Constants ◽  
Vickers Hardness ◽  
First Principles ◽  
Second Order ◽  
First Principles Calculations ◽  
Modulus Ratio ◽  
Third Order ◽  
Lattice Constants ◽  
Third Order Elastic Constants

First-principles calculations combined with homogeneous deformation methods are used to investigate the second- and third-order elastic constants of YNi2B2C with tetragonal structure. The predicted lattice constants and second-order elastic constants of YNi2B2C agree well with the available data. The effective second-order elastic constants are obtained from the second- and third-order elastic constants for YNi2B2C. Based on the effective second-order elastic constants, Pugh’s modulus ratio, Poisson’s ratio, and Vickers hardness of YNi2B2C under high pressure are further investigated. It is shown that the ductility of YNi2B2C increases with increasing pressure.

scholarly journals First Principles Computations of Second-Order Elastic Constants (SOEC) and Equations of State of Rutile TiO2

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Ghous Narejo ◽  
Warren F. Perger
Keyword(s):  
Equation Of State ◽  
Elastic Constants ◽  
First Principles ◽  
Equations Of State ◽  
Second Order ◽  
Lattice Parameters ◽  
Experimental Results ◽  
Basis Sets ◽  
Computational Results ◽  
Rutile Tio2

First principles computations of second-order elastic constants (SOECs) and bulk moduli (B) are carried out by ELASTCON and equation of state (EOS) programs. Computational results of lattice parameters, elastic constants, and bulk moduli are obtained with a wide variety of potentials and a limited combination of basis sets and are compared with computational and experimental results by other researchers in the field. DFT hybrid potentials provided the best comparison with the experiment.

Combining First-Principles and Data Modeling for the Accurate Prediction of the Refractive Index of Organic Polymers

2017 ◽  
Author(s):  
Mohammad Atif Faiz Afzal ◽  
Chong Cheng ◽  
Johannes Hachmann
Keyword(s):  
First Principles ◽  
Data Modeling ◽  
Accurate Prediction ◽  
Index Of Refraction ◽  
Structure Theory ◽  
Organic Polymers ◽  
Number Density ◽  
Lorenz Equation ◽  
In Silico Studies ◽  
Wide Range

Organic materials with a high index of refraction (RI) are attracting considerable interest due to their potential application in optic and optoelectronic devices. However, most of these applications require an RI value of 1.7 or larger, while typical carbon-based polymers only exhibit values in the range of 1.3–1.5. This paper introduces an efficient computational protocol for the accurate prediction of RI values in polymers to facilitate in silico studies that an guide the discovery and design of next-generation high-RI materials. Our protocol is based on the Lorentz-Lorenz equation and is parametrized by the polarizability and number density values of a given candidate compound. In the proposed scheme, we compute the former using first-principles electronic structure theory and the latter using an approximation based on van der Waals volumes. The critical parameter in the number density approximation is the packing fraction of the bulk polymer, for which we have devised a machine learning model. We demonstrate the performance of the proposed RI protocol by testing its predictions against the experimentally known RI values of 112 optical polymers. Our approach to combine first-principles and data modeling emerges as both a successful and highly economical path to determining the RI values for a wide range of organic polymers.

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