Phasego 3.0: Automatic analysis of synthesis and decomposition conditions for compounds

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• 作者：Zhong-Li Liu^a ; ^{zl.liu@163.com" class="auth_mail" title="E-mail the corresponding author} ; Qian-Ku Hu^b ; Hai-Yan Wang^b ; Xiao-Feng Li^a
• 关键词：Synthesis conditions ; Decomposition conditions ; Gibbs free energy ; Phase diagram
• 刊名：Computer Physics Communications
• 出版年：2016
• 出版时间：December 2016
• 年：2016
• 卷：209
• 期：Complete
• 页码：197-198
• 全文大小：299 K

文摘

In this paper, we present a revised version of Phasego 2.0 toolkit which is a package for automatic phase diagram analysis and anharmonic effect corrections. In this new version, the automatic synthesis/decomposition conditions analysis functionality is added to predict the stable field of compounds based on the quasi-harmonic approximation (QHA) or the anharmonic free energy corrections. The analysis about the synthesis/decomposition conditions provides the vital information for new materials design under high pressure and temperature.

New version program summary

Program Title:Phasego3

Program Files doi:http://dx.doi.org/10.17632/xp7gvmrxrg.1

Licensing provisions: GNU General Public License, version 3

Programming language: Python (versions 2.4 and later)

Journal reference of previous version: Computer Physics Communications, 197 (2015) 341

Does the new version supersede the previous version?: Yes

External libraries: Numpy [1], Scipy [2], Matplotlib [3]

Nature of problem: A compound can be synthesized from different components and at different pressure and temperature conditions. It can also decompose into several possible products at specific pressure and temperature conditions according to the thermodynamic equilibrium relations. There are many possibilities in products when pressure and/or temperature vary. However, it is very complicated to analyze which chemical process can really proceed according to the Gibbs free energy criteria.

Solution method: All kinds of possible combinations of reactants/products before/after the synthesis/decomposition of a compound can be automatically analyzed according to the atom number equality of each atom species on the two sides of the chemical equation. The comparison and analysis of the Gibbs free energies among all the possible combinations of reactants/products are automated in the updated version. The boundaries between the compound and the possible combinations of reactants/products can also be plotted and labeled automatically. The reactants for a compound or the decomposition products of a compound can be predicted and located accurately.

Reasons for the new version: We have improved the package considerably to perform the synthesis/decomposition conditions analysis for compounds. In the new version, the phase boundaries between the compound and the possible combinations of reactants/products can also be plotted automatically. The reactants for a compound and the decomposition products of a compound can be predicted and located accurately. These functionalities are very helpful to the researchers in the new materials design community.

Summary of revisions:

•$•$ The functionality of synthesis/decomposition conditions analysis is added.

•$•$ The automatic chemical equations search functionality has been added according to the atom number equality of each atom species on the two sides of a chemical equation.

•$•$ The phase diagram can be analyzed by taking into account the synthesis/decomposition conditions.

•$•$ The energy and volume now are treated with per formula unit (f.u.) instead of per atom.

•$•$ The previously calculated phonon Helmholtz free energies can be imported for further calculations.

•$•$ Some parameters are renamed or added.

•$•$ A number of bugs have been corrected.

Restrictions: The restrictions are from the phonon DOS calculations. The accuracy of the previously calculated phonon DOS also affects that of the final results.

Unusual features: The synthesis/decomposition conditions of compounds can be analyzed and plotted automatically.

Additional comments: The new version of this package can perform the synthesis/decomposition conditions analysis based on the free energies calculated from the phonon density of states data from many methods, e.g. the molecular dynamics (MD) simulations [4], the self-consistent ab initio lattice dynamics (SCAILD) calculations [5], or other simulation methods.

Running time: The examples provided in the distribution take less than 5 minute to run.

References:

[1]

www.numpy.org.

[2]

www.scipy.org.

[3]

www.matplotlib.org.

[4]

O. Hellman, I. A. Abrikosov, and S. I. Simak, Phys. Rev. B 84 (2011) 180301.

[5]

Souvatzis, P. and Eriksson, O. and Katsnelson, M. I. and Rudin, S. P., Phys. Rev. Lett., 100 (2008) 095901.