Bethe Salpeter Equation Spectra for Very Large Systems with Thousands of Electrons or More

具有数千个或更多电子的超大型系统的 Bethe Salpeter 方程谱

• 批准号: 2245253
• 负责人: Daniel Neuhauser
• 金额: $ 49.92万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2245253&HistoricalAwards=false
• 关键词: Bethe; Salpeter; Equation; Spectra; Very

With support from the Chemical Theory, Models and Computational Methods program in the Division of Chemistry, Professor Daniel Neuhauser of UCLA is developing methods for determining the optical properties of very large molecular systems. These properties play a critical role in broad applications of organic and inorganic energy materials, including semiconducting nanoparticles, organic supramolecular structures, and organic photovoltaic nanostructures. The ability to characterize very large systems with thousands of atoms computationally is critical for the manipulation and control of these new materials and systems, and for the design of future systems. Toward this end, the Neuhauser group will develop a stochastic formalism to solve the Bethe-Salpeter Equation (BSE) for characterizing the absorption spectrum of very large chemical systems. BSE is known to predict accurately the absorption properties of molecular and solid-state systems. The use of these proposed stochastic methods is expected to enable scaling up to very large systems of thousands of atoms with tens of thousands of electrons. This work will be incorporated into a new code-based General Chemistry course and outreach activities to underserved groups.Typically the BSE is too computationally costly to consider for molecules larger than few hundred atoms due to the generation and application of the screened Coulomb exchange, W. The Neuhauser research group will undertake to develoop three specific methodology advances to the BSE: linear scaling generation of the action of W, sparse stochastic compression and sampling for storage of huge W matrices, practically quadratic scaling of the stochastic application of W within the BSE, a time-dependent Hartree-Fock (TDHF) with W-based exchange kernels, and stochastic representation of first-order dynamic corrections. Specifically, the action of the screened Coulomb interaction will be separated into a convolutional exchange-like portion that is to be systematically improved to resemble the true effective interaction, and a small remainder that should easily be stochastically sampled. Together, these innovations are expected to couple to yield a method for simulating nanoscale systems of thousands of electrons in active orbitals. If successful, these modification of the Bethe-Salpeter Equation are expected to have far-reaching scientific impact.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.

在化学理论，模型和计算方法的支持下，UCLA的Daniel Neuhauser教授正在开发确定非常大分子系统的光学特性的方法。这些特性在有机和无机材料的广泛应用中起着至关重要的作用，包括半导体的纳米颗粒，有机超分子结构和有机光伏纳米结构。具有数千原子在计算上表征非常大的系统的能力对于对这些新材料和系统的操纵和控制以及未来系统的设计至关重要。为此，Neuhauser组将开发一种随机形式主义，以解决Bethe-Salpeter方程（BSE），以表征非常大的化学系统的吸收光谱。已知BSE可以准确预测分子和固态系统的吸收特性。这些提出的随机方法的使用有望使具有数万个电子的数千原子的非常大的系统扩展。这项工作将被纳入一个新的基于代码的通用化学课程和向服务不足的组中进行外展活动。从计算机上，由于筛选的库仑交换的生成和应用，BSE在计算上太昂贵了，无法考虑大于几百个原子的分子，W。Neuhauser研究小组将在spristor spristion and spry sprypers and spemertom spemertion and selling selling selling selling selling specryper：在巨大的W矩阵中，W在BSE中的随机应用实际上是二次缩放，这是一个与时间有关的Hartree-fock（TDHF），具有基于W的交换内核，以及一阶动力校正的随机表示。具体而言，筛选的库仑相互作用的作用将分成一个类似卷积的交换部分，该部分将被系统地改进以类似于真正的有效相互作用，其余部分则很容易随机抽样。总之，预计这些创新将产生一种模拟活性轨道中数千个电子的纳米级系统的方法。如果成功的话，这些对伯特盐方程的修改预计将产生深远的科学影响。该奖项反映了NSF的法定任务，并且使用基金会的知识分子优点和更广泛的审查标准，被认为值得通过评估来获得支持。