流行的理论方法预测和是非平面的
Damian Moran1, Andrew C Simmonett, Franklin E Leach
1Center for Computational Chemistry, University of Georgia, Athens, Georgia 30602, USA.
Journal of the American Chemical Society
|July 20, 2006
概括
平面通常由于计算错误而被错误地预测为稳定. 平衡的基础集对于准确确定和类似的pi-delocalized分子的非平面结构至关重要.
科学领域:
- 计算化学是一种计算化学.
- 量子化学是一种量子化学.
- 分子建模分子建模
背景情况:
- 平面是一种基本的芳香分子.
- 对分子几何学的准确预测在化学中是必不可少的.
- 以前的研究表明,的预测结构存在差异.
研究的目的:
- 为了调查计算失败预测平面是最小的.
- 为了确定和相关分子中虚假的虚构频率的原因.
- 确定必要的计算条件,以准确预测平面的平面性.
主要方法:
- 利用了各种基础集的第二阶MøllerPlesset扰动理论 (MP2).
- 分析振动频率以识别表明不稳定的虚构模式.
- 研究了基础集不完整性错误 (BSIE) 在计算预测中的作用.
主要成果:
- 使用不平衡的Pople类型基础集的MP2计算错误地预测了平面.
- 虚假的虚构频率与外平面扭曲 (椅子和船形状) 相对应.
- 这种失败在其他pi-delocalized系统中也可以观察到,比如皮里丁和纳夫他林.
结论:
- 一个不平衡的基础集不完整性错误 (BSIE) 是导致平面的不准确预测的原因.
- 相关的波函数方法需要平衡的,相关性一致的基础集,以进行可靠的竞技场几何预测.
- 这些发现凸显了基础集合选择在计算化学中的重要性.
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