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Two new approaches for electronic structure: Partition density functional theory and potential functional theory.

机译:电子结构的两种新方法:分区密度泛函和势泛函。

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摘要

In this work I discuss two new approaches to the electronic structure problem. Both these approaches share the same goal of making electronic structure calculations faster and more accurate and both involve the popular electronic structure method of density functional theory (DFT). The first is potential functional theory which makes use of semiclassical methods to understand and improve density functional theory. In particular it explains why local approximations in DFT work as well as they do and why the generalized gradient approximations developed in the late 1980's, early 1990's were needed at all. I also develop direct potential functional approximations for the density and kinetic energy density for particles in an arbitrary potential with hard walls. As such they avoid solving the difficult Schrodinger's equation. I demonstrate their accuracy on a simple system. The second is partition density functional theory (PDFT) which solves for molecular properties while only requiring calculations on smaller fragments. This would greatly speed up computations and allow much large systems to be studied. I give a detailed derivation of PDFT before demonstrating its formal exactness on three types of system. Both these approaches have the potential to cure some of the problems DFT suffers from and these possible consequences are discussed.
机译:在这项工作中,我讨论了两种解决电子结构问题的新方法。这两种方法都具有使电子结构计算更快,更准确的相同目标,并且都涉及流行的密度泛函理论(DFT)的电子结构方法。第一个是潜在功能理论,它利用半经典方法来理解和改进密度泛函理论。尤其是,它解释了为什么DFT中的局部逼近也能正常工作,以及为什么在1980年代末,1990年代初完全需要广义梯度逼近。我还针对具有硬壁的任意势能中的粒子的密度和动能密度开发了直接势函数近似。因此,它们避免了求解困难的薛定'方程。我在一个简单的系统上演示了它们的准确性。第二种是分配密度泛函理论(PDFT),它可以解决分子特性,而只需要对较小的片段进行计算。这将大大加快计算速度,并允许研究大型系统。在演示PDFT在三种类型的系统上的形式正确性之前,我会详细介绍它。这两种方法都有可能解决DFT所遇到的一些问题,并讨论了这些可能的后果。

著录项

  • 作者

    Elliott, Peter A.;

  • 作者单位

    University of California, Irvine.;

  • 授予单位 University of California, Irvine.;
  • 学科 Physics Condensed Matter.;Chemistry Physical.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 105 p.
  • 总页数 105
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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