scholarly journals A study of thermodynamic properties of quadratic exponential-type potential in D-dimensions

2018 ◽  
Vol 64 (6) ◽  
pp. 608 ◽  
Author(s):  
Uduakobong Sunday Okorie
Keyword(s):  
Molecular Dynamics ◽  
Free Energy ◽  
Thermodynamic Properties ◽  
Exponential Type ◽  
Factorization Method ◽  
Vibrational Entropy ◽  
Energy Eigenvalues ◽  
Modified Factorization Method ◽  
Vibrational Partition Function ◽  
Type Potential

We solved the Schrodinger equation with Quadratic Exponential-Type Potential (QEP) model in D-dimensions using the Modified factorization method. The energy eigenvalues and total wavefunctions were obtained in a Gauss hypergeometric form. The thermodynamic properties including vibrational partition function, vibrational mean energy, vibrational mean free energy and vibrational entropy have been calculated for the electronic state of (X1 Σ +g) Rubidium (Rb2) dimer. The QEP discussed can be applied extensively in Physics and Chemistry, especially in molecular dynamics.

scholarly journals First-Principles Study of Mechanical and Thermodynamic Properties of Binary and Ternary CoX (X = W and Mo) Intermetallic Compounds

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1404
Author(s):  
Yunfei Yang ◽  
Changhao Wang ◽  
Junhao Sun ◽  
Shilei Li ◽  
Wei Liu ◽  
...  
Keyword(s):  
Free Energy ◽  
Thermodynamic Properties ◽  
Gibbs Free Energy ◽  
Density Functional ◽  
Vibrational Entropy ◽  
Functional Theory ◽  
Lattice Constants ◽  
The Density Functional Theory ◽  
Ductile Behavior ◽  
Pseudo Potential

In this study, the structural, elastic, and thermodynamic properties of DO19 and L12 structured Co3X (X = W, Mo or both W and Mo) and μ structured Co7X6 were investigated using the density functional theory implemented in the pseudo-potential plane wave. The obtained lattice constants were observed to be in good agreement with the available experimental data. With respect to the calculated mechanical properties and Poisson’s ratio, the DO19-Co3X, L12-Co3X, and μ-Co7X6 compounds were noted to be mechanically stable and possessed an optimal ductile behavior; however, L12-Co3X exhibited higher strength and brittleness than DO19-Co3X. Moreover, the quasi-harmonic Debye–Grüneisen approach was confirmed to be valid in describing the temperature-dependent thermodynamic properties of the Co3X and Co7X6 compounds, including heat capacity, vibrational entropy, and Gibbs free energy. Based on the calculated Gibbs free energy of DO19-Co3X and L12-Co7X6, the phase transformation temperatures for DO19-Co3X to L12-Co7X6 were determined and obtained values were noted to match well with the experiment results.

Spatial Redistribution of Niobium Additives Near Nickel Surfaces

1995 ◽  
Vol 408 ◽  
Author(s):  
Leonid S. Muratov ◽  
Bernard R. Cooper
Keyword(s):  
Molecular Dynamics ◽  
Free Energy ◽  
Harmonic Approximation ◽  
Lattice Relaxation ◽  
Pure Nickel ◽  
Quantum Mechanical ◽  
Concentration Limit ◽  
Vibrational Entropy ◽  
Quantum Mechanical Calculations ◽  
Spatial Redistribution

AbstractThe spatial redistribution of niobium atoms near the surface of pure nickel has been considered in the low niobium concentration limit. The calculation of free energy includes lattice relaxation around niobium atoms by using molecular dynamics (MD) incorporating atomistic potentials based on ab-initio quantum mechanical calculations and includes vibrational entropy phenomenologically within the local harmonic approximation.

Calculation of Thermodynamic Properties for B2-YCu Intermetallics with Molecular Dynamics

2012 ◽  
Vol 581-582 ◽  
pp. 798-802
Author(s):  
Long Shan Xu ◽  
Yu Rong Wu
Keyword(s):  
Molecular Dynamics ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Elastic Constants ◽  
Calculated Data ◽  
Lattice Parameter ◽  
Linear Increase ◽  
Vibrational Entropy ◽  
Ductile Behavior ◽  
Experimental Findings

The thermodynamic properties of YCu intermetallics with B2 structure are investigated with molecular dynamics. The thermodynamic properties at various temperatures, such as lattice parameter, cohesive energy, enthalpy of formation, elastic constants, heat capacity, vibrational entropy and vibrational free energy are computed. The present calculated results show good agreements with available experimental and previous calculated data. The calculated elastic constants suggested that YCu compound has a mostly ductile behavior. This prediction match well with experimental findings. At high temperature, the heat capacity tends to a constant with obeys the classical equipartition law. At 300K, the heat capacity of YCu is 23.80J mol-1 K-1. The calculated coefficient of thermal volume expansion α increases sharply at T<20K. When T<300K α gradually approaches a linear increase with enhanced temperature and the propensity of increment becomes moderate. At T=300K, the value of α is 5.88×10-5K-1. And those data enrich thermodynamic data-base for YCu compound.

scholarly journals Energy Eigenvalues and Eigenfunctions of a Diatomic Molecule in Quadratic Exponential-type Potential

2020 ◽  
Vol 3 (2) ◽  
pp. 240-251
Author(s):  
ES Eyube ◽  
U Wadata ◽  
SD Najoji
Keyword(s):  
Exponential Type ◽  
State Energy ◽  
Bound State ◽  
Wave Functions ◽  
Closed Form Expression ◽  
Bound State Energy ◽  
Form Expression ◽  
Radial Wave ◽  
Energy Eigenvalues ◽  
Type Potential

We have employed the exact quantization rule to obtain closed form expression for the bound state energy eigenvalues of a molecule in quadratic exponential-type potential. To deal with the spin-orbit centrifugal term of the effective potential energy function, we have used a Pekeris-type approximation scheme, we have also obtained closed form expression for the normalized radial wave functions by solving the Riccati equation with quadratic exponential-type potential. Using our derived energy eigenvalue formula, we have deduced expressions for the bound state energy eigenvalues of the Hulthén, Eckart and Deng-Fan potentials, considered as special cases of the quadratic exponential-type potential. Our deduced energy eigenvalues are in excellent agreement with those in the literature. We have computed bound states energy eigenvalues for six diatomic molecules viz: HCl, LiH, H2, SeH, VH and TiH. Our results are in total agreement with existing results in the literature for the s-wave and in good agreement for higher quantum states. By solving the Riccati equation, we have obtained normalized radial wave functions of the quadratic exponential-type potential, our results show higher probabilities of finding the molecule in the region 0.1 ≤ y ≤ 0.2

Thermodynamics of the System Ag2se-Ag2s: A Molecular Dynamics Study

1995 ◽  
Vol 398 ◽  
Author(s):  
A. Smith ◽  
R. Ravelo ◽  
N. Pingitore
Keyword(s):  
Molecular Dynamics ◽  
Phase Diagram ◽  
Free Energy ◽  
Binary System ◽  
Ion Mobility ◽  
Vibrational Entropy ◽  
Adiabatic Switching ◽  
Diffusion Rates

ABSTRACTWe report on Molecular Dynamics (MD) studies of free energy and vibrational entropy differences of the binary system Ag2Se-Ag2S as function of temperature. We have employed the methods of adiabatic switching and temperature integration over a reversible path to obtain the phase diagram. We discuss the nature of the entropy difference in terms of ion mobility and previous MD calculations of diffusion rates in these systems.

scholarly journals Thermodynamic properties of improved deformed exponential-type potential (IDEP) for some diatomic molecules

2020 ◽  
Vol 17 ◽  
pp. 103078 ◽  
Author(s):  
U.S. Okorie ◽  
A.N. Ikot ◽  
E.O. Chukwuocha ◽  
G.J. Rampho
Keyword(s):  
Thermodynamic Properties ◽  
Exponential Type ◽  
Diatomic Molecules ◽  
Type Potential

Prediction of Alkanolamine pKa Values by Combined Molecular Dynamics Free Energy Simulations and ab initio Calculations

2019 ◽  
Author(s):  
Javad Noroozi ◽  
William Smith
Keyword(s):  
Molecular Dynamics ◽  
Free Energy ◽  
Ab Initio Calculations ◽  
Gas Phase ◽  
Quantum Chemical ◽  
Phase Reaction ◽  
Pka Values ◽  
Gas Phase Reaction ◽  
Reaction Free Energy ◽  
Energy Simulations

We use molecular dynamics free energy simulations in conjunction with quantum chemical calculations of gas phase reaction free energy to predict alkanolamines pka values. <br>

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