Bridging the gap between accurate ab initio many-body theory and simple density-functionals

弥合精确的从头算多体理论和简单的密度泛函之间的差距

基本信息

批准号：
EP/M029131/1
负责人：
Andrew Michael Teale
金额：
$ 12.69万
依托单位：
University of Nottingham
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2015
资助国家：
英国
起止时间：
2015 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FM029131%2F1
关键词：
Bridging gap between accurate ab

项目摘要

Density-functional theory is at the forefront of today's quantum mechanical approaches for the description of the molecules and materials that are the building blocks for a diverse range of technologies. The key to the predictive power and accuracy of the approach is the treatment of the quantum mechanical exchange and correlation interactions of the electrons. Present-day approximations for these contributions are limited to a narrow comfort zone of applicability - the work in this proposal will develop new approximations to significantly expand the range of viable applications. Methods to describe the exchange and correlation contributions to the energy are often relatively simple models based on the electronic density distribution and its gradient. Higher accuracy can be obtained using first-principles techniques based on the many-electron wave function. In this work we construct a common framework for the comparison of these expensive high accuracy approaches with simple density-functional approximations. This framework gives new insight into the development of new simple models - in particular the higher derivatives of the density are highlighted as a key variables for the description of electronic correlation. Functionals based on this quantity will be developed in this work, opening the way to more accurate and robust correlation treatments - removing error cancellations that plague present-day approximations.

密度功能理论是当今量子力学方法的最前沿，用于描述分子和材料，这些分子和材料是多种技术范围的基础。该方法的预测能力和准确性的关键是对电子的量子机械交换和相关相互作用的处理。这些贡献的当前近似限制仅限于适用性的狭窄舒适性区 - 该提案中的工作将开发新的近似值，以大大扩大可行应用的范围。描述对能量的交换和相关性贡献的方法通常是基于电子密度分布及其梯度的相对简单的模型。使用基于多电子波函数的第一原理技术可以获得更高的精度。在这项工作中，我们构建了一个共同的框架，用于比较这些昂贵的高精度方法和简单的密度函数近似值。该框架为新的简单模型的开发提供了新的见解 - 特别是密度的较高衍生物被强调为描述电子相关性的关键变量。基于此数量的功能将在这项工作中开发，为更准确，更健壮的相关处理开辟了道路 - 消除了困扰当今近似值的误差取消。