In Search of an Optimum Reference

在化学系化学理论、模型和计算方法项目的支持下，加州大学欧文分校（UCI）的Filipp Furche旨在开发、实施、评估和应用一种新的计算化学电子结构方法家族，以解决当前理论的关键局限性。这些限制阻碍了我们在催化、药物设计、大气化学和量子材料等领域准确预测和模拟能量和性质的能力。Furche提出的“最佳参考”（OR）方法有望通过设计将当前方法的“参考偏差”最小化，并有望将电子结构计算的范围扩展到迄今为止难以捉摸的系统和性质。在这个项目中开发的方法将通过Turbomole量子化学软件向公众开放。该项目将通过UCI的量子科学跨学科项目和针对那些本来参与研究机会有限的学生的高中外展项目来支持教育和劳动力准备。该项目建立并旨在推广以前的发展，如轨道优化和布鲁克纳方法，以及自洽随机相位近似方法。虽然量子化学中越来越复杂的相关处理的发展已经为“表现良好”的系统产生了非常精确的方法，但目前使用的几乎所有电子相关方法的阿喀琉斯之踵是它们对参考状态的非物理依赖，即对感兴趣的物理量子状态的定性准确且易于计算的近似。Furche的工作旨在开发稳定的OR方法，以四个命题为指导：(i) OR应该在一个定义良好的度量中最小化与感兴趣的物理状态的距离，（ii）具有定义良好的物理意义并产生模型化学，（iii）总能量应该在OR处是平稳的，（iv）作为参考的函数的相关能必须符合明确的，受控的近似。所得到的方法将被评估其捕获开壳d和f元素化合物系统的磁性和自旋特性的能力，这对现有方法来说尤其具有挑战性。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Chemical Theory, Models and Computational Methods Program in the Division of Chemistry, Filipp Furche of the University of California, Irvine (UCI) aims to develop, implement, evaluate, and apply a new family of electronic structure methods of computational chemistry to address critical limitations of current theories. These limitations hamper our ability to predict and simulate accurately energies and properties in areas such as catalysis, drug design, atmospheric chemistry, and quantum materials. The ‘optimum reference’ (OR) methods proposed by Furche promise to minimize by design the ‘reference bias’ of current methods and are expected to extend the scope of electronic structure calculations to hitherto elusive systems and properties. The methods developed in this project will be made available to the public through the Turbomole quantum chemistry software. The program will support education and workforce readiness through an interdisciplinary program in quantum science at UCI and a high school outreach program aimed at students who otherwise would have limited opportunities to participate in research.This project builds on and aims to generalize previous developments such as orbital optimization and Brueckner methods, as well as self-consistent random phase approximation methods. While the development of ever more sophisticated correlation treatments in quantum chemistry has produced exceedingly accurate methods for "well behaved" systems, the Achilles' heel of virtually all electron correlation methods in use today is their unphysical dependence on a reference state, i.e., a qualitatively accurate, and readily computable approximation to the physical quantum state of interest. Furche's work aims to develop stable OR methods guided by four propositions: (i) The OR should minimize the distance to the physical state of interest in a well-defined metric, (ii) have a well-defined physical meaning and give rise to a model chemistry, (iii) the total energy should be stationary at the OR, (iv) the correlation energy as a functional of the reference must be amenable to explicit, controlled approximations. The resulting methods will be assessed for their ability to capture magnetic and spin properties of open-shell d- and f-element compounds systems that are particularly challenging for available approaches.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.