scholarly journals Thermodynamic Parameters of PbTe Crystals: DFT-Calculations

2015 ◽  
Vol 16 (1) ◽  
pp. 28-33
Author(s):  
D. M. Freik ◽  
B. P. Volochanska ◽  
T. O. Parashchuk
Keyword(s):  
Density Functional Theory ◽  
Free Energy ◽  
Electronic Structure ◽  
Thermodynamic Parameters ◽  
Quantum Chemical ◽  
Density Functional ◽  
Cubic Phase ◽  
Functional Theory ◽  
Temperature Dependences ◽  
Analytical Expressions

Based on the analysis of the crystal NaCl type and electronic structure of cubic phase CdS crystals the cluster models have been built for calculation of the geometric and thermodynamic parameters. According to density functional theory (DFT) and using the hybrid valence base set B3LYP the temperature dependence of the energy ΔE and the enthalpy ΔH of formation, Gibbs free energy ΔG, entropy ΔS, specific heat at constant volume CV and pressure CP of the crystals have been found. The analytical expressions of the temperature dependences of presented thermodynamic parameters which was approximated from the quantum- chemical calculations data and with using mathematical package Maple 14 have been received.

scholarly journals Thermodynamic Parameters of Lead Sulfide Crystals in the Cubic Phase

2015 ◽  
Vol 16 (4) ◽  
pp. 649-653
Author(s):  
B. P. Volochanska
Keyword(s):  
Thermodynamic Parameters ◽  
Density Functional ◽  
Calculated Data ◽  
Density Functional Theory Method ◽  
Cubic Phase ◽  
Chemical Calculation ◽  
Functional Theory ◽  
Temperature Dependences ◽  
Computer Calculations ◽  
Analytical Expressions

Geometric and thermodynamic parameters of cubic PbS crystals were obtained using the computer calculations of the thermodynamic parameters within density functional theory method DFT. Cluster models for the calculation were based on the analysis of the crystal and electronic structure. Temperature dependence of energy ΔE and ΔH enthalpy, Gibbs free energy ΔG, heat capacity at constant pressure CP and volume CV, entropy ΔS were determined on the basis of ab initio calculations of the crystal structure of molecular clusters. Analytical expressions of temperature dependences of thermodynamic parameters which were approximated with quantum-chemical calculation points using mathematical package Maple 14 were presented. Experimental results compared with theoretically calculated data.

scholarly journals Density Functional Theory; a New Route for Structural and Thermodynamic Parameters Calculations

2018 ◽  
Vol 14 (1) ◽  
pp. 5312-5325
Author(s):  
M.S. Meikhail ◽  
W. Awad ◽  
A.M. Abdelghany
Keyword(s):  
Density Functional Theory ◽  
Free Energy ◽  
Thermodynamic Parameters ◽  
Polymer Blend ◽  
Thermodynamic Functions ◽  
Density Functional ◽  
Theoretical Density ◽  
Functional Theory ◽  
Polymeric Matrices ◽  
Extensive Variable

Structural and thermodynamic parameters of the studied virgin polymeric matrices poly e-caprolactone (PCL), Chitosan (Chi) and their polymer blend were investigated using theoretical density functional theory (DFT). Thermodynamic functions were calculated based on vibrational frequencies and optimized geometrical coordinates in the temperature range 25-1000 °K which cannot be amended easily. Calculated free energy was found to be convex in terms of extensive variable and concave in terms of intensive ones.

scholarly journals CALCULATION OF THE ELECTRONIC STRUCTURE OF SOME EPOXY MOLECULES BY THE DFT METHOD

2021 ◽  
pp. 32-34
Author(s):  
V. A. Babkin ◽  
D. S. Andreev ◽  
E. S. Titova ◽  
A. V. Ignatov ◽  
R. O. Boldyrev ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Quantum Chemical Calculation ◽  
Quantum Chemical ◽  
Density Functional ◽  
Dft Method ◽  
Chemical Calculation ◽  
Functional Theory ◽  
The Density Functional Theory

In this work, we performed a quantum-chemical calculation of some epoxy molecules: 1,2-epoxy-butene, 1,2-epoxy-2-methylpropane, 1,2 epoxyethane by the density functional theory DFT. An optimized geometric and electronic structure of these compounds is obtained. It was found that the studied epoxides belong to the class of very weak СH-acids (pKa = 28-30).

scholarly journals Thermodynamic Parameters of Lead Sulfide Chrystals in the Cubic Phase

2016 ◽  
Vol 3 (1) ◽  
pp. 15-22 ◽  
Author(s):  
T. Parashchuk ◽  
A. Zagorodnyuk ◽  
L. Nykyruy ◽  
B. Volochanska ◽  
Т. Mazur
Keyword(s):  
Crystal Structure ◽  
Thermodynamic Parameters ◽  
Density Functional ◽  
Constant Pressure ◽  
Calculated Data ◽  
Molecular Clusters ◽  
Cubic Phase ◽  
Chemical Calculation ◽  
Functional Theory ◽  
Analytical Expressions

Geometric and thermodynamic parameters of cubic PbS crystals were obtained using thecomputer calculations of the thermodynamic parameters within density functional theory methodDFT. Cluster models for the calculation based on the analysis of the crystal and electronicstructure. Temperature dependence of energy ΔE and enthalpy ΔH, Gibbs free energy ΔG, heatcapacity at constant pressure CP and constant volume CV, entropy ΔS were determined on thebasis of ab initio calculations of the crystal structure of molecular clusters. Analytical expressions oftemperature dependences of thermodynamic parameters which were approximated withquantum-chemical calculation points have been presented. Experimental results compared withtheoretically calculated data.

scholarly journals Isomers of (L)-Diiodotyrosine - A DFT Treatise

2021 ◽  
pp. 347-361
Author(s):  
Lemi Türker
Keyword(s):  
Density Functional Theory ◽  
Free Energy ◽  
Hydrogen Bonding ◽  
Quantum Chemical ◽  
Density Functional ◽  
Heat Of Formation ◽  
Functional Theory ◽  
Free Energy Of Formation ◽  
Ionic Forms ◽  
Energy Of Formation

(L)-Diiodotyrosine isomers are considered within the realm of density functional theory at the level of B3LYP/6-311+G(d,p). Their zwitter ionic forms are considered as well. All the structures are electronically stable, have exothermic heat of formation and favorable Gibbs free energy of formation values. Within the limitations of the method the zwitter ionic forms are not different from the corresponding parent structures in the vacuum conditions and no hydrogen bonding seems to exist between the NH2 and COOH groups. Some structural, quantum chemical and spectral data have been collected and discussed.

scholarly journals Interaction of Carmustine Tautomers with Adenine - DFT Study

2020 ◽  
pp. 63-76
Author(s):  
Lemi Türker
Keyword(s):  
Density Functional Theory ◽  
Free Energy ◽  
Quantum Chemical ◽  
Density Functional ◽  
Equilibrium Concentration ◽  
Dft Study ◽  
Functional Theory ◽  
Dna And Rna ◽  
Free Energy Of Formation ◽  
Energy Of Formation

Carmustine is a chemotherapic substance used in treatment of various cancers. In the present study, within the constraints of density functional theory (B3LYP/6-31++G(d,p)), tautomerism of carmustine has been investigated. It may undergo 1,3-type proton tautomerism, however the obtained data for vacuum conditions indicated that the equilibrium concentration of the enol type tautomer should be low. Afterwards, interactions of those tautomers with adenine, a constituent base of DNA and RNA, have been investigated. The composites (1:1) are electronically stable. Their heat of formations are exothermic and the free energy of formation values are favorable. Some of their calculated properties (structural, physicochemical and quantum chemical) are obtained and discussed.

Doping effects on the geometric and electronic structure of tin clusters

2019 ◽  
Vol 21 (44) ◽  
pp. 24478-24488 ◽  
Author(s):  
Martin Gleditzsch ◽  
Marc Jäger ◽  
Lukáš F. Pašteka ◽  
Armin Shayeghi ◽  
Rolf Schäfer
Keyword(s):  
Density Functional Theory ◽  
Electronic Structure ◽  
Density Functional ◽  
Beam Deflection ◽  
Functional Theory ◽  
Doping Effects ◽  
Depth Analysis ◽  
Trajectory Simulations

In depth analysis of doping effects on the geometric and electronic structure of tin clusters via electric beam deflection, numerical trajectory simulations and density functional theory.

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