Phasego: A toolkit for automatic calculation and plot of phase diagram
Phasego: A toolkit for automatic calculation and plot of phase diagram
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Phasego：自动计算和绘制相图的工具包
DOI：
10.1016/j.cpc.2015.01.023
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发表时间：
2014-10
影响因子：
6.3
通讯作者：
Zhong-Li Liu
中科院分区：
文献类型：
--
作者：
Zhong-Li Liu
Phasegopackage从第一性原理计算得到的声子态密度中提取亥姆霍兹自由能。通过状态方程拟合，在温度/压力一定的情况下，得到了吉布斯自由能随压力/温度的变化关系。该方法基于准谐波近似（QHA），计算出所有感兴趣结构之间可能存在的相边界，最后自动绘制相图。对于单相分析，Phasegocan可以数值推导出许多性质，例如热膨胀系数、体积模量、热容量、热压力、Hugoniot压力-体积-温度关系、Grüneisen参数和德拜温度。为了检验它的相变分析能力，我在这里举两个例子：半导体GaN和金属Fe。在GaN的情况下，PhaseGo自动确定并绘制所提供的锌钛矿（ZB）、纤锌矿（WZ）和岩盐（RS）结构之间的相边界。在Fe的情况下，结果表明，在高温下，电子热激发自由能校正相当大地改变体心立方（bcc）、面心立方（fcc）和六方密堆积（hcp）结构之间的相边界。http://cpc.cs.qub.ac.uk/summaries/AEVQ_v1_0.htmlProgram爱尔兰许可条款：GNU通用公共许可证，第3版分布式程序中的行，包括测试数据等：837140号分布式程序的字节数，包括测试数据等：8816053分发格式：tar. gz编程语言：Python（2.4及更高版本）计算机：任何可以运行Python（2.4及更高版本）的计算机操作系统：任何可以运行Python的操作系统RAM：10 M bytes分类：7.8外部例程：Numpy [1]，Scipy [2]，Matplotlib [3]问题性质：当环境压力和温度升高到足够高的值时，材料通常会发生结构相变。相变过程遵循吉布斯自由能最低原则。除了静态能量，电流密度泛函理论（DFT）计算可以很容易地给出晶格振动的声子态密度，从声子的亥姆霍兹自由能减少。在QHA的框架下，可以得到吉布斯自由能，用于分析高温高压下的相稳定性和相变。问题是从DFT计算中提取吉布斯自由能，并自动分析多个结构之间的高压和高温相边界。求解方法：借助数值插值技术，可以获得在固定温度/压力下吉布斯自由能作为压力/温度的函数。然后，根据吉布斯自由能最低的原理，在固定的温度/压力下，通过扫描压力/温度，可以自动确定和绘制基于QHA的相边界。限制：限制来自QHA，它部分考虑了非谐效应。不同寻常的特点：可以自动确定和绘制许多结构之间的相边界，这大大提高了相变分析的效率。除了每个单一结构的一些基本热力学性质外，Hugoniot压力-体积-温度关系也会自动简化。
ThePhasegopackage extracts the Helmholtz free energy from the phonon density of states obtained by the first-principles calculations. With the help of equation of states fitting, it reduces the Gibbs free energy as a function of pressure/temperature at fixed temperature/pressure. Based on the quasi-harmonic approximation (QHA), it calculates the possible phase boundaries among all the structures of interest and finally plots the phase diagram automatically. For the single phase analysis,Phasegocan numerically derive many properties, such as the thermal expansion coefficients, the bulk moduli, the heat capacities, the thermal pressures, the Hugoniot pressure–volume–temperature relations, the Grüneisen parameters, and the Debye temperatures. In order to check its ability of phase transition analysis, I present here two examples: semiconductor GaN and metallic Fe. In the case of GaN,Phasegoautomatically determined and plotted the phase boundaries among the provided zinc blende (ZB), wurtzite (WZ) and rocksalt (RS) structures. In the case of Fe, the results indicate that at high temperature the electronic thermal excitation free energy corrections considerably alter the phase boundaries among the body-centered cubic (bcc), face-centered cubic (fcc) and hexagonal close-packed (hcp) structures.Program summaryProgram title:PhasegoCatalogue identifier:AEVQ_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEVQ_v1_0.htmlProgram obtainable from:CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions:GNU General Public License, version 3No. of lines in distributed program, including test data, etc.:837140No. of bytes in distributed program, including test data, etc.:8816053Distribution format:tar.gzProgramming language:Python (versions 2.4 and later).Computer:Any computer that can run Python (versions 2.4 and later).Operating system:Any operating system that can run Python.RAM:10 M bytesClassification:7.8.External routines:Numpy [1], Scipy [2], Matplotlib [3]Nature of problem:Materials usually undergo structural phase transitions when the environmental pressure and temperature are elevated to high enough values. The phase transition process obeys the principle of lowest Gibbs free energy. In addition to the static energy, current density functional theory (DFT) calculations can easily give the phonon density of states of lattice vibrations, from which the Helmholtz free energy of phonons are reduced. Then Gibbs free energy can be achieved for the analysis of phase stability and phase transition at high pressure and temperature within the framework of QHA. The problem is to extract the Gibbs free energies from the DFT calculations and automatically analyze the high pressure and temperature phase boundaries among a number of structures.Solution method:With the help of numerical interpolation techniques, the Gibbs free energy as a function of pressure/temperature at fixed temperature/pressure can be obtained. Then the QHA based phase boundaries can be automatically determined and plotted by scanning the pressure/temperature at fixed temperature/pressure according to the principle of lowest Gibbs free energy.Restrictions:The restriction is from the QHA which takes partially into account the anharmonic effects.Unusual features:The phase boundaries among a number of structures can be automatically determined and plotted, which largely improve the efficiency of phase transition analysis. In addition to some basic thermodynamic properties of each single structure, the Hugoniot pressure–volume–temperature relations are also automatically reduced.Additional comments:This …
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DOI：
10.1088/0953-8984/1/11/002
发表时间：
1989-03
期刊：
Journal of Physics: Condensed Matter
影响因子：
--
作者：
Pascal Vinet;J. H. Rose;J. Ferrante;John R. Smith-
通讯作者：
Pascal Vinet;J. H. Rose;J. Ferrante;John R. Smith-
DOI：
10.1036/1097-8542.209200
发表时间：
2014
期刊：
Access Science
影响因子：
--
作者：
D. J. Doornbos
通讯作者：
D. J. Doornbos
影响因子：
64.8
作者：
O. Lodge
通讯作者：
O. Lodge
DOI：
10.1002/0470845856
发表时间：
2002-05
期刊：
--
影响因子：
--
作者：
J. H. Westbrook;R. Fleischer
通讯作者：
J. H. Westbrook;R. Fleischer
影响因子：
6.3
作者：
Otero-de-la-Roza, A.;Abbasi-Perez, David;Luana, Victor
通讯作者：
Luana, Victor