EAGER: Rung-Reduced Density Functionals for Cost-Capped Ab Initio Molecular Dynamics

该项目涉及开发新的交换相关势，这些势在计算上便宜，并且可以在更大的系统上实现从头算分子动力学。这种非传统的、有前途的、但有风险的方法开发了这些相关潜力，使该项目符合EAGER的要求。背景是从头算分子动力学模拟对新材料特性预测模拟的重要性日益增加。这使我们对原子尺度的过程有了详细的了解，这些过程会影响体的性质，即使是在实验上无法达到的条件下。与振动频率、电离势等最流行的方法相比，PI基于约束（不适合数据库）的函数将分子结合能误差降低了两倍。最近的一项重大进展提供了一条诱人的、极不寻常的途径来探索这一建议，该进展基于GGA阶上第一个完全非经验的无轨道动能泛函。有四个领域的影响更为广泛。成功将改变从头算分子动力学模拟复杂、具有挑战性的材料，特别是在部门和组级机器上，通过保持标准的Kohn-Sham成本比例尽可能低。纯密度泛函理论本身的某些基本方面（超越模拟）将得到实质性的澄清，包括雅各布斯阶梯的间距。国际科学将通过合作者及其在墨西哥的学生的参与得到加强。博士后学者将受益于高水平的学术学徒。技术概述：该项目涉及开发新的交换相关电位，这些电位在计算上便宜，并且可以在更大的系统上实现从头算MD。提出的解决方案是近似交换相关密度泛函只依赖于电子数密度及其空间导数，而不是明确地依赖于Kohn-Sham轨道。这种非传统的、有前途的、但有风险的方法使该项目符合EAGER的要求。背景是从头算分子动力学模拟对新材料特性预测模拟的重要性日益增加。这使我们对原子尺度的过程有了详细的了解，这些过程会影响体的性质，即使是在实验上无法达到的条件下。与振动频率、电离势等最流行的方法相比，PI基于约束（不适合数据库）的函数将分子结合能误差降低了两倍。这种“阶降”策略将从元广义梯度近似（meta-GGA）泛函中去除轨道，得到高度精细的GGA泛函。最近的一项重大进展提供了一条诱人的、极不寻常的途径来探索这一建议，该进展基于GGA阶上第一个完全非经验的无轨道动能泛函。有四个领域的影响更为广泛。成功将改变从头算分子动力学模拟复杂、具有挑战性的材料，特别是在部门和组级机器上，通过保持标准的Kohn-Sham成本比例尽可能低。纯DFT本身的某些基本方面（超出模拟）将得到实质性的澄清，包括雅各布斯阶梯梯级的间距。国际科学将通过合作者及其在墨西哥的学生的参与得到加强。博士后学者将受益于高水平的学术学徒。

NONTECHNICAL SUMMARYThe project involves the development of new exchange correlation potentials that are computationally cheap and would enable ab initio molecular dynamics on larger systems. This unconventional, promising, but risky approach to developing these correlation potentials qualifies the project for EAGER. Context is the growing importance of ab initio molecular dynamics simulations for predictive simulation of novel material properties. This gives detailed insight into atomic-scale processes that affect bulk properties, even for experimentally inaccessible conditions. The PI's constraint-based (not fitted to data bases) functionals reduce molecular binding energy errors by a factor of two compared to the most popular methods with vibration frequencies, ionization potentials, etc. An enticing and highly unusual route to be explored in this proposal is provided by a recent major advance based on the first fully non-empirical orbital-free kinetic energy functional at the GGA rung. There are four areas of broader impact. Success will transform ab initio molecular dynamics simulations of complicated, challenging materials, particularly on department and group-level machines by keeping standard Kohn-Sham cost-scaling as low as possible. Certain fundamental aspects of pure Density Functional Theory itself (beyond simulations) will be substantially clarified, including spacing of the Jacobs' ladder rungs. International science will be enhanced by involvement with collaborators and their student in Mexico. The postdoctoral scholar will benefit from a high-level academic apprenticeship.TECHNICAL SUMMARYThe project involves the development of new exchange correlation potentials that are computationally cheap and would enable ab initio MD on larger systems. The proposed solution is to approximate exchange-correlation density functionals dependent only on the electron number density and its spatial derivatives, and not explicitly on the Kohn-Sham orbitals. This unconventional, promising, but risky approach qualifies the project for EAGER. Context is the growing importance of ab initio molecular dynamics simulations for predictive simulation of novel material properties. This gives detailed insight into atomic-scale processes that affect bulk properties, even for experimentally inaccessible conditions. The PI's constraint-based (not fitted to data bases) functionals reduce molecular binding energy errors by a factor of two compared to the most popular methods with vibration frequencies, ionization potentials, etc. This "rung reduction" strategy will remove the orbitals from meta-generalized gradient approximation (meta-GGA) functionals to get highly refined GGA functionals. An enticing and highly unusual route to be explored in this proposal is provided by a recent major advance based on the first fully non-empirical orbital-free kinetic energy functional at the GGA rung. There are four areas of broader impact. Success will transform ab initio molecular dynamics simulations of complicated, challenging materials, particularly on department and group-level machines by keeping standard Kohn-Sham cost-scaling as low as possible. Certain fundamental aspects of pure DFT itself (beyond simulations) will be substantially clarified, including spacing of the Jacobs' ladder rungs. International science will be enhanced by involvement with collaborators and their student in Mexico. The postdoctoral scholar will benefit from a high-level academic apprenticeship.