Dielectric functions, their properties and their relation to observables: Investigations using the Chapidif program for the case of aluminum

IF 7.2 2区物理与天体物理 Q1 COMPUTER SCIENCE, INTERDISCIPLINARY APPLICATIONS

Computer Physics Communications Pub Date : 2025-05-12 DOI:10.1016/j.cpc.2025.109657

Maarten Vos , Pedro L. Grande

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引用次数: 0

Abstract

We introduce the program ‘Chapidif’ by describing a study of the properties of aluminum based on simple model dielectric functions. These are generally not available from first principle, and one is forced to describe them in terms of (a sum of) model dielectric functions. The Chapidif program is used to visualize these, check their sum rules and the mathematical relation between the real and imaginary part. In addition, several properties related to the interaction of charged particles (here either protons or electrons) with matter are derived and compared with experiment. By having a single program that can calculate a range of properties, it becomes easy to ensure that the model used is not just able to describe a single observable, but it is transferable, i.e. describes reasonably well a larger range of material properties. A reflection electron energy loss measurement is used as an example of how a comparison of calculated results with experiment can be used to improve the model and thus enhance the quality of the properties derived from the dielectric function.

Program summary

Program Title: Chapidif

CPC Library link to program files: https://doi.org/10.17632/7wmxg69v7x.1

Licensing provisions: CC BY NC 3.0

Programming language: Python, C++

Nature of problem: Frequency- and momentum-dependent dielectric functions can describe a wide variety of material properties. The quantity has many intricate mathematical properties and is subject to constraints due to sum rules. The Chapidif program can be used to visualize a dielectric function, check its sum rules, and calculate a wide range of quantities, in particular relating to the interaction of protons and electrons with matter. Details of how the classical and quantum-based dielectric functions are implemented are given elsewhere [1]. The program makes it easy to investigate if the assumed dielectric function has the required mathematical properties and how the choice of the model dielectric function and the corresponding parameters influences the calculated observables such as ion stopping and electron inelastic mean free path.

Solution method: The program consists of a Python/Tkinter user interface and C++ backend that does the actual calculations. Results are displayed using Matplotlib library and, if desired, text-based output files containing the input parameters used and the calculated quantities can be generated.

References

[1]
M. Vos, P.L. Grande, RPA dielectric functions: streamlined approach to relaxation effects, binding and high momentum dispersion, J. Phys. Chem. Solids 198 (2025) 112470, https://doi.org/10.1016/j.jpcs.2024.112470.

查看原文本刊更多论文

介电函数及其性质及其与观测值的关系：用Chapidif程序研究铝的情况

通过描述基于简单模型介电函数的铝的特性研究，介绍了Chapidif程序。这些通常不能从第一性原理得到，人们被迫用模型介电函数的（总和）来描述它们。Chapidif程序用于将它们可视化，检查它们的和规则以及实部和虚部之间的数学关系。此外，推导了与带电粒子（这里是质子或电子）与物质相互作用有关的几个性质，并与实验进行了比较。通过拥有一个可以计算一系列属性的单一程序，可以很容易地确保所使用的模型不仅能够描述单一的可观察到的，而且它是可转移的，即合理地描述更大范围的材料属性。以反射电子能量损失测量为例，说明如何利用计算结果与实验结果的比较来改进模型，从而提高由介电函数得出的性质的质量。程序摘要程序标题：ChapidifCPC库链接到程序文件：https://doi.org/10.17632/7wmxg69v7x.1Licensing条款：CC BY NC 3.0编程语言：Python， c++问题性质：频率和动量相关的介电函数可以描述各种各样的材料特性。这个量具有许多复杂的数学性质，并受到求和规则的约束。Chapidif程序可用于可视化介电函数，检查其和规则，并计算广泛的数量，特别是与质子和电子与物质的相互作用有关。经典和基于量子的介电函数如何实现的细节在其他地方给出[1]。该程序可以很容易地研究假设的介电函数是否具有所需的数学性质，以及模型介电函数和相应参数的选择如何影响计算的观测值，如离子停止和电子非弹性平均自由程。解决方法：该程序由Python/Tkinter用户界面和执行实际计算的c++后端组成。使用Matplotlib库显示结果，如果需要，可以生成包含所使用的输入参数和计算数量的基于文本的输出文件。王志强，张志强，RPA介电函数：简化的弛豫效应，结合和高动量色散，物理学报。化学。固体198 (2025)112470,https://doi.org/10.1016/j.jpcs.2024.112470。

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来源期刊

Computer Physics Communications 物理-计算机：跨学科应用

CiteScore

12.10

自引率

3.20%

发文量

287

审稿时长

5.3 months

期刊介绍： The focus of CPC is on contemporary computational methods and techniques and their implementation, the effectiveness of which will normally be evidenced by the author(s) within the context of a substantive problem in physics. Within this setting CPC publishes two types of paper. Computer Programs in Physics (CPiP) These papers describe significant computer programs to be archived in the CPC Program Library which is held in the Mendeley Data repository. The submitted software must be covered by an approved open source licence. Papers and associated computer programs that address a problem of contemporary interest in physics that cannot be solved by current software are particularly encouraged. Computational Physics Papers (CP) These are research papers in, but are not limited to, the following themes across computational physics and related disciplines. mathematical and numerical methods and algorithms; computational models including those associated with the design, control and analysis of experiments; and algebraic computation. Each will normally include software implementation and performance details. The software implementation should, ideally, be available via GitHub, Zenodo or an institutional repository.In addition, research papers on the impact of advanced computer architecture and special purpose computers on computing in the physical sciences and software topics related to, and of importance in, the physical sciences may be considered.