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Approaching chemical accuracy in the electronic structure theory of solids: Linearly-scaling periodic local coupled cluster method in combination with explicitly correlated Møller-Plesset perturbation theory

接近固体电子结构理论中的化学精度：线性尺度周期性局域耦合簇方法与显式相关的 Mäller-Plesset 微扰理论相结合

基本信息

批准号：
179161791
负责人：
Privatdozent Dr. Denis Usvyat
金额：
--
依托单位：
Arbeitsgruppe Theoretische Chemie
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2010
资助国家：
德国
起止时间：
2009-12-31 至 2021-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/179161791?language=en
关键词：
Approaching chemical accuracy electronic structure

项目摘要

Quantum chemical hierarchy of electronic structure methods allows for systematic improvement of the accuracy of the calculations. This feature, which is lacking in DFT, makes the wave-function approach very powerful for first-principle predictions. In particular, the CCSD(T) method is considered a gold standard of quantum chemistry, as at the basis set limit it is known to agree with experiment within the chemical accuracy for a broad range of closed shell systems. Unfortunately, accurate quantum chemical models are considerably more expensive that standard DFT and possess unfavorably high scaling of the computational cost with system size. This becomes especially critical for periodic systems, which are the target systems of this project.One way to defeat the prohibitive scaling wall is the local correlation scheme. The project aims at a continuation of work on development a hierarchy of periodic wave-function-based methods within the local correlation framework. In the first phase of this project the main focus was on correcting the basis set incompleteness and domain errors by implementing local periodic MP2-F12 method. It allows one in a triple-zeta-based calculation to get the result close to the MP2 basis set limit. Having this method at hand, we can now concentrate on the LMP2 method error. It is planned to implement the hierarchy of the post MP2 models: starting from ring-LCCD and LMP3 via LCCSD to the target method LCCSD(T). The final energy will be represented as a sum of two components: the LMP2-F12 energy and the post-MP2 energy correction i.e. the energy difference between LCCSD(T) and LMP2. The method will be able to treat periodic systems at the level, close to the CCSD(T) at the basis set limit, at the same time exhibiting linear scaling of the computational cost with not a very high prefactor. The developments, described in the present proposal, will be included in the publicly available CRYSCOR code. The possibility to treat periodic systems at such a level will be very useful for the community in both experimental and theoretical investigations. The method will also possess several important advantages over other techniques that can presently be used for CCSD(T) calculations on periodic systems. For example, in contrast to fragment-based methods, it will be free of the errors due the finite-cluster representation and straightforward to use. Compared to the plane-wave CCSD(T) implementation of VASP, the local direct-space approach will be based on a multilevel local approximation and thus attain high efficiency and linear scaling of the computational cost. Another strong side of the method will be the straightforward applicability to surfaces, polymers or molecules. Additionally, the direct-space implementation will allow for a very promising follow-up development of automatic force-field generator, based on direct fitting of individual coupled cluster contributions.

电子结构方法的量子化学层次结构允许系统地提高计算的准确性。这个特点，这是缺乏DFT，使波函数方法非常强大的第一原理预测。特别是，CCSD（T）方法被认为是量子化学的黄金标准，因为在基组极限下，已知它在广泛的封闭壳层系统的化学准确度内与实验一致。不幸的是，精确的量子化学模型比标准DFT昂贵得多，并且具有不利的高计算成本与系统大小的比例。这对于周期性系统（本项目的目标系统）尤为关键。克服这一限制性尺度墙的一种方法是局部相关方案。该项目旨在继续开展工作，在局部相关性框架内开发一系列基于周期波函数的方法。在本项目的第一阶段，主要的重点是通过实施局部周期MP2-F12方法来校正基组不完整性和域误差。它允许在基于三重ζ的计算中得到接近MP2基组极限的结果。有了这个方法，我们现在可以专注于LMP 2方法的误差。计划实现后MP2模型的层次结构：从环LCCD和LMP 3开始，经过LCCSD到目标方法LCCSD（T）。最终能量将表示为两个分量的总和：LMP 2-F12能量和MP2后能量校正，即LCCSD（T）和LMP 2之间的能量差。该方法将能够处理周期性系统的水平，接近CCSD（T）的基组限制，在同一时间表现出线性缩放的计算成本，而不是一个很高的前因子。本提案中所述的发展情况将列入可公开获得的CSCOR代码。在这样的水平上处理周期系统的可能性将在实验和理论研究中对社区非常有用。该方法也将拥有几个重要的优势，目前可以用于CCSD（T）计算周期系统的其他技术。例如，与基于片段的方法相比，它将没有由于有限簇表示而产生的错误，并且使用简单。与VASP的平面波CCSD（T）实现相比，局部直接空间方法将基于多级局部近似，从而获得高效率和计算成本的线性缩放。该方法的另一个优点是直接适用于表面，聚合物或分子。此外，直接空间的实施将允许一个非常有前途的自动力场发生器的后续发展，直接拟合的基础上，个别耦合集群的贡献。