对分子相关电子结构的最佳实体空间轨道的直接确定
Edward F Valeev1, Robert J Harrison2, Adam A Holmes1
1Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States.
Journal of chemical theory and computation
|October 4, 2023
概括
这项研究引入了一种新的真实空间方法,用于使用优化的正规轨道计算精确的原子和分子能量. 这种方法克服了传统基础集的局限性,为相关电子结构计算提供了更高的精度.
科学领域:
- 计算化学计算化学
- 量子化学 是一个量子化学.
- 材料科学 材料科学 材料科学
背景情况:
- 相关电子结构计算的传统方法通常依赖于原子轨道 (AO) 基础集.
- 这些AO基础集可能会遭受不良条件和线性依赖问题,限制准确性和适用性.
- 为准确的能量评估开发强大的数值方法对于理解分子行为至关重要.
研究的目的:
- 展示一种数值方法,用于确定近乎精确的正规轨道,用于评估相关的原子和分子状态的能量.
- 呈现一个真实空间轨道表示,避免传统的AO基础集的局限性.
- 将这种新方法的精度与最先进的解决方案进行比较.
主要方法:
- 将能量拉格朗的最小化以获得最佳的或非正常轨道.
- 使用实体空间中的多分辨率光谱元素基础,以适应性精细化精度.
- 采用可变电子结构模型,选择配置交互 (CI),用于能源计算.
主要成果:
- 达到精度与轻原子的最先进的原子CI溶解器相比较的能量.
- 计算的电子能量比AO基础集合扩展的能量要准确得多.
- 即使在线性依赖问题阻止AO基础集使用时,也成功确定了能量.
结论:
- 现实空间轨道表示为高端相关电子结构模型提供了可行且可能优于AO表示的替代方案.
- 该方法在计算上是可行的,在单个节点上优化了100多个轨道.
- 预计将进一步提高计算效率.
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