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Response of Periodic Systems to External Electric and Magnetic Fields

周期性系统对外部电场和磁场的响应

基本信息

批准号：
219844080
负责人：
Professor Dr. Michael Springborg
金额：
--
依托单位：
Department of Chemistry and Biochemistry
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2012
资助国家：
德国
起止时间：
2011-12-31 至 2016-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/219844080?language=en
关键词：
Response Periodic Systems External Electric

项目摘要

During the last roughly eight years the applicant together with a colleague in the US has been working on developing a method for studying the electronic and structural responses of quasi-linear chain compounds in external electrostatic fields where we have used a model Hamiltonian. The approach has been implemented into one and is being implemented into another ab initio program packages for polymers. This project is focusing on fundamental aspects of extending the approach to higher dimensions, to the treatment of magnetic fields, to delocalized basis functions (like plane waves), and to various fundamental aspects of the approach. As in our previous work, all theoretical approaches shall be analyzed through model calculations both for large, finite systems and for infinite, periodic systems. The use of models allows for studying in detail convergence behavior and for treating different types of systems. Both for electric and for magnetic fields, r is replaced by operators involving the derivatives with respect to k when studying infinite, periodic systems. Ultimately, this means that phase factors of the orbitals become important and that the band structures are non-unique for infinite periodic systems exposed to electromagnetic fields. Furthermore, it is not obvious how to identify excitation energies for such systems, partly because the approach is formulated for systems with completely filled bands. Also these aspects shall be studied through carefully designed model systems. Finally, the problems of presently used approximate density-functionals in describing the response of chain systems to electric fields shall be studied, too, by considering models

在过去的大约八年中，申请人与美国的同事一起一直致力于开发一种用于研究准线性链化合物在外部静电场中的电子和结构响应的方法，其中我们使用了模型哈密顿量。该方法已经实施到一个，并正在实施到另一个从头算程序包的聚合物。这个项目的重点是基本方面的扩展方法更高的维度，磁场的治疗，离域基函数（如平面波），以及各种基本方面的方法。与我们以前的工作一样，所有的理论方法都要通过模型计算来分析，既要对大的有限系统，也要对无限的周期系统。模型的使用允许详细研究收敛行为和治疗不同类型的系统。对于电场和磁场，在研究无限周期系统时，r被涉及k的导数的算子所取代。最终，这意味着轨道的相位因子变得重要，并且对于暴露于电磁场的无限周期系统，能带结构是非唯一的。此外，如何确定这种系统的激发能并不明显，部分原因是该方法是为具有完全填充带的系统制定的。此外，这些方面应通过精心设计的模型系统进行研究。最后，还将通过考虑模型来研究目前使用的近似密度泛函在描述链系统对电场的响应方面的问题