对于5f-元素的密度功能紧密结合的有效参数化:一个Th-O案例研究
Chang Liu1, Néstor F Aguirre1, Marc J Cawkwell1
1Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, United States.
对f元素进行密度函数紧密结合 (DFTB) 模型的参数化在计算上是昂贵的. 本研究介绍了有效的方法,包括按轨道组进行校正和加速优化,以减少f元素DFTB模型的参数和计算成本.
科学领域:
- 计算化学计算化学
- 材料科学 材料科学 材料科学
- 量子化学 是一个量子化学.
背景情况:
- 对f元素物种的密度功能紧密结合 (DFTB) 模型进行参数化是具有挑战性的,因为有大量可调节的参数.
- 参数优化的计算成本随着轨道数的增加而增加,这使得f元素与主要组元素相比变得昂贵.
- 准确的f元素的DFTB哈密尔顿数对于理解它们在结合相互作用中的作用至关重要.
研究的目的:
- 开发有效的方法来缓解DFTB对f元素的参数化中的大型参数空间挑战.
- 为了减少参数数量和计算成本,同时保持f元素DFTB模型的准确性.
- 为Th-O系统参数化DFTB哈密尔顿式,并将其应用于研究ThO2纳米粒子.
主要方法:
- 开发了对两中心键积的新型组对轨道校正函数,以与元素数线性地减少参数.
- 对于较大的训练集,使用小批量布罗伊登弗莱彻戈德法尔布沙诺 (BFGS) 方法加速参数优化.
- 在目标函数中使用一个随机优化器来克服局部最小值.
主要成果:
- 在保持精度的同时,将f元素的参数数量减少了40%以上.
- 通过使用大型训练集 (6322个结构) 成功对Th-O系统的DFTB哈密尔顿式进行了参数化.
- 优化的参数集 (LANL-ThO) 与对集群和批量ThO2的DFT计算属性有很好的一致性.
结论:
- 提出的高效方法显著降低了f元素的DFTB参数化计算成本和参数数量.
- 这种方法显示出具有挑战性的DFTB参数化任务的潜力,涉及具有高角度动量元素.
- LANL-ThO参数集为研究ThO2纳米粒子和相关系统提供了可靠的工具.
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