Applying simulation results of high-boron compounds of structure at the atomic level to estimate their chemical hardness

2020 ◽  
Vol 2020 (1) ◽  
pp. 8-16
Author(s):  
V.V. Kartuzov ◽  
◽  
N.M. Rozhenko ◽  
K.O. , Efimova ◽  
V.M. Danilyuk ◽  
...  

Determining the macrocharacteristics of materials based on the results of ab initio calculations is one of the most relevant and promising areas of research. One of the most important performance characteristics of the material is its hardness. The presented approach to determining the chemical Vickers hardness of substances based on using ab initio calculated values of atomization energy and molar volume atomic clusters, which are elements of the structure of the studied compounds. Clusters of boron, aluminum and magnesium borides of different atomic structure, which are obtained using simulation modeling of their evolution, are considered. The results of quantum chemical calculations of the values of atomization energy and molar volume of the considered fragments, obtained using the Gaussian'03 software package in the framework of the theory of electron density functional in the B3LYP / STO-3G approximation, are presented. The hardness of materials, structural elements of which are tested atomic clusters, obtained by the developed approach are presented. The calculated hardness is compared with its values determined by both experimental and other theoretical methods. The comparison showed a high correlation of the obtained results with the experimental data already at the cluster size equal to 12—25 atoms. Analysis of the results of applying the proposed approach to various modifications of boron and some boron-containing compounds showed that quantum-chemical calculations of atomic energy and molar volume values within the cluster model provide the ability to establish reliable estimates of the hardness of existing compounds of this class. The developed approach, together with simulation modeling of the evolution of hypothetical phases, can also be applied to predict their hardness. Keywords: boron, borides, cluster model, Vickers hardness.

2020 ◽  
Vol 16 (2) ◽  
pp. 93-103 ◽  
Author(s):  
Piotr Kawczak ◽  
Leszek Bober ◽  
Tomasz Bączek

Background: Pharmacological and physicochemical classification of bases’ selected analogues of nucleic acids is proposed in the study. Objective: Structural parameters received by the PCM (Polarizable Continuum Model) with several types of calculation methods for the structures in vacuo and in the aquatic environment together with the huge set of extra molecular descriptors obtained by the professional software and literature values of biological activity were used to search the relationships. Methods: Principal Component Analysis (PCA) together with Factor Analysis (FA) and Multiple Linear Regressions (MLR) as the types of the chemometric approach based on semi-empirical ab initio molecular modeling studies were performed. Results: The equations with statistically significant descriptors were proposed to demonstrate both the common and differentiating characteristics of the bases' analogues of nucleic acids based on the quantum chemical calculations and biological activity data. Conclusion: The obtained QSAR models can be used for predicting and explaining the activity of studied molecules.


2021 ◽  
Author(s):  
Soichi Shirai ◽  
Shinji Inagaki

Practical strategies for suppressing Si–C cleavage during the polycondensation of organosilanes were presented based on ab initio quantum chemical calculations of model compounds.


2009 ◽  
Vol 50 (2) ◽  
pp. 195-200 ◽  
Author(s):  
Yu. V. Frolov ◽  
A. V. Vashchenko ◽  
A. G. Mal’kina ◽  
B. A. Trofimov

2020 ◽  
Author(s):  
Sopanant Datta ◽  
Taweetham Limpanuparb

<p>This article presents theoretical data on geometric and energetic features of halobenzenes and xylenes. Data were obtained from <i>ab initio</i> geometry optimization and frequency calculations at HF, B3LYP, MP2 and CCSD levels of theory on 6-311++G(d,p) basis set. In total, 1504 structures of halobenzenes, three structures of xylenes and one structure of benzene were generated and processed by custom-made codes in Mathematica. The quantum chemical calculation was completed in Q-Chem software package. Geometric and energetic data of the compounds are presented in this paper as supplementary tables. Raw output files as well as codes and scripts associated with production and extraction of data are also provided.</p>


2011 ◽  
Vol 134 (4) ◽  
pp. 044535 ◽  
Author(s):  
Bhaswati Bhattacharya ◽  
Barnali Jana ◽  
Debosreeta Bose ◽  
Nitin Chattopadhyay

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