Developing Thermal Hybrid Exchange-Correlation Functionals for Accurate Prediction of Transport and Optical Properties of Warm Dense Plasmas

获得诺贝尔奖的密度泛函理论（DFT）方法已被广泛用于重要应用，以更好地理解自然的物理和化学，以及改善我们的日常生活。DFT应用的例子包括发明具有特定功能的材料，了解化学反应以获得更好的产品，以及设计治疗癌症的药物。DFT的成功依赖于材料中粒子如何相互作用的近似精度，即所谓的交换相关（XC）自由能量密度泛函。到目前为止，大多数可用的xc功能仅限于零温度情况。在这个研究项目中，有限温度的xc泛函将被开发，以显着提高DFT在等离子体物理和材料研究中的预测能力。该研究项目的成果有望在行星科学、天体物理学、核聚变能源、国防应用等多个科学领域和应用领域产生重大影响，并为发现更好的材料和设计有效的药物提供工具，对社会产生积极影响。在温暖稠密的条件下，物质在宇宙中大量存在——从实验室中产生的激波和惯性约束聚变内爆，到行星核心和天体物理物体，如褐矮星和白矮星。深入了解热致密物质、非理想和“外来”等离子体的性质，是解开行星和天体物理科学中许多谜团的关键；例如，土星上可能的氢氦分离。在这种极端条件下可靠地预测物质的输运和光学性质在很大程度上取决于DFT方法所要求的XC泛函的准确性。在该项目中，将建立一个三步研究计划，通过以下方式开发精确的有限温度混合xc泛函：(i)评估可用的热自由能泛函性能，以确定当前泛函失效的状态条件；开发热混合和热筛选混合XC功能，这些功能对应于那些被证明对零温度情况下的能量差距准确的功能；（iii）将开发的热混合xc函数应用于热稠密等离子体模拟，以实验为基准，并为广泛的计算科学界提供有用的软件。特别是，pi将以开源的形式发布最终软件包，并将其合并到现有Quantum-Espresso和ABINIT计算软件包的标准发行版中。这将使该项目得到更广泛的发展。高级网络基础设施办公室的软件集群对这方面特别感兴趣，该办公室为该奖项提供了共同资金。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。

The Nobel Prize-winning method of density-functional theory (DFT) has been widely used for important applications to better understand the physics and chemistry of nature, as well as to improve our daily life. Examples of DFT applications range from inventing materials of specific functions, to understanding chemical reactions for better products, to designing drugs to cure cancers. The success of DFT relies on the accuracy of the approximation of how particles in a material interact with each other, the so-called exchange-correlation (XC) free-energy density functional. So far, most of the available XC-functionals have been limited to zero-temperature cases. In this research project, finite-temperature XC-functionals will be developed to significantly improve the predictive capability of DFT for plasma-physics and materials studies. The outcome of this research project is expected to make a significant difference in a variety of scientific fields and applications such as planetary science, astrophysics, fusion-energy and national defense applications, as well as to make a positive impact on the society through delivering tools for discovering better materials and designing efficient drugs.Matter at warm dense conditions exists vastly in the universe -- from shocks and inertial confinement fusion implosions created in laboratories to planetary cores and astrophysical objects such as brown and white dwarfs. Thorough understanding of the properties of warm-dense matter, non-ideal and "exotic" plasmas hold the key to unravel many mysteries in planetary and astrophysical sciences; for example, the possible H-He demixing on Saturn. Reliably predicting the transport and optical properties of matter at such extreme conditions heavily depends on the accuracy of XC functionals required by the DFT method. In this project, a three-step research program will be established to develop accurate finite-temperature hybrid XC-functionals by: (i) Assessing the available thermal free-energy functional performance to identify the state conditions wherein those current functionals fail; (ii) Developing thermal-hybrid and thermal-screened hybrid XC functionals that correspond to those proven to be accurate for the energy gap in the zero-temperature case; and (iii) Applying the developed thermal hybrid XC-functionals to warm-dense-plasma simulations to benchmark with experiments and deliver a useful software to the broad computational science community. In particular, the PIs will release the resulting software package as open source and incorporate it into the standard distribution for the existing Quantum-Espresso and ABINIT computational packages. This will allow a wider growth of the project. This aspect is of special interest to the software cluster in the Office of Advanced Cyberinfrastructure, which has provided co-funding for this award.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.