在辅助场量子蒙特卡罗的激发状态
Ankit Mahajan1, Sandeep Sharma2, Shiwei Zhang3
1Department of Chemistry, Columbia University, New York, New York 10027, USA.
The Journal of chemical physics
|January 23, 2026
概括
辅助场量子蒙特卡罗 (AFQMC) 准确计算量子化学中的激发状态. 这种方法提供了一个可扩展的,更准确的替代方案,以运动方程合集群方法的低兴奋状态.
科学领域:
- 量子化学是一种量子化学.
- 计算物理学的计算物理.
- 电子结构理论 电子结构理论
背景情况:
- 计算激发状态对于理解分子特性和反应至关重要.
- 传统的方法,如运动方程合集群 (EOM-CCSD),在计算上可能昂贵,并且对于某些系统可能缺乏准确性.
- 辅助场量子蒙特卡罗 (AFQMC) 是电子结构计算的一个新兴方法.
研究的目的:
- 系统地研究AFQMC的准确性和可扩展性,用于计算低兴奋状态.
- 将AFQMC的表现与EOM-CCSD等既定方法进行比较.
- 为了确定AFQMC激发状态计算的最佳试验状态.
主要方法:
- 利用对称性来准三重激发状态作为AFQMC中的基本状态问题.
- 采用截断的运动方程与单双激发 (EOM-CCSD) 结合集群作为开放单元激发状态的试验状态.
- 基准AFQMC对中小分子和聚烯的计算.
主要成果:
- AFQMC成功地使用受限制的开放决定因素计算了三重激发状态.
- 与主动空间方法相比,EOM-CCSD试验状态提高了开放单元激发状态的准确性.
- AFQMC的结果显示系统性地比EOM-CCSD更高的准确性,在开单片机中,激发能误差减少了大约一半.
- AFQMC 实现了每样本成本扩展 O(N^6).
结论:
- AFQMC是一种可行且准确的方法来计算低兴奋状态,特别是当EOM-CC三倍数在计算上是不可行的时.
- 对于激发状态计算,AFQMC为EOM-CCSD提供了一个可扩展和更准确的替代方案.
- 试验状态的选择显著影响了AFQMC对开放单元状态的准确性.
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