The Quantum Self-Consistent Ab-Initio Lattice Dynamics package (QSCAILD) is a python library that computes temperature-dependent effective 2nd and 3rd order interatomic force constants in crystals, including anharmonic effects. QSCAILD’s approach is based on the quantum statistics of a harmonic model. The program requires the forces acting on displaced atoms of a solid as an input, which can be obtained from an external code based on density functional theory, or any other calculator. This article describes QSCAILD’s implementation, clarifies its connections to other methods, and illustrates its use in the case of the SrTiO₃ cubic perovskite structure.

Program summary

Program Title: QSCAILD

CPC Library link to program files: https://doi.org/10.17632/y4c922fwtf.1

Licensing provisions: GNU General Public License version 3.0

Programming language: Python

External routines/libraries: MPI, NumPy, SciPy, spglib, phonopy, sklearn

Nature of problem: Calculation of effective interatomic force constants at finite temperature

Solution method: Regression analysis of forces from density functional theory coupled with a harmonic model of the quantum canonical ensemble, performed in an iterative way to achieve self-consistency of the phonon spectrum

中文翻译：

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量子自洽从头算晶格动力学

量子自洽Ab-Initio晶格动力学软件包（QSCAILD）是一个python库，用于计算晶体中与温度相关的有效2级和3级原子间力常数，包括非谐效应。QSCAILD的方法基于谐波模型的量子统计。该程序需要将作用在固体的位移原子上的力作为输入，该力可以从基于密度泛函理论的外部代码或任何其他计算器中获得。本文介绍了QSCAILD的实现，阐明了其与其他方法的联系，并说明了其在SrTiO ₃立方钙钛矿结构中的使用。

计划摘要

节目名称： QSCAILD

CPC库链接到程序文件： https : //doi.org/10.17632/y4c922fwtf.1

许可条款： GNU通用公共许可证3.0版

编程语言： Python

外部例程/库： MPI，NumPy，SciPy，spglib，phonopy，sklearn

问题性质：有限温度下有效原子间力常数的计算

解决方法：以密度泛函理论结合量子规范系的调和模型对力进行回归分析，以迭代方式进行，以实现声子谱的自洽