将双混合函数与rSCAN相结合,可以获得固态C化学转移,精度低于ppm
Harry Brough1, Chris W Cook1,2, John M Griffin1
1Department of Chemistry, Lancaster University, Lancaster, LA1 4YB, UK. m.peach@lancaster.ac.uk.
Physical chemistry chemical physics : PCCP
|July 15, 2025
概括
当与单体正相结合时,rSCAN功能改善了NMR屏蔽计算,特别是当使用像mPW2PLYP-CPCM这样的双混合功能来提高NMR结晶学中的精度时.
科学领域:
- 计算化学计算化学
- 固态NMR光谱学 固态NMR光谱学
- 核磁共振晶体学 NMR 晶体学
背景情况:
- 准确预测NMR屏蔽对于NMR晶体学中的光谱分配和晶体结构精细化至关重要.
- 定期计算通常使用GGA函数 (PBE,BLYP),但单体校正可以改善局部电子结构处理.
- 超-GGA功能rSCAN在几何优化方面表现有前途,但其在周期屏蔽计算中的性能在很大程度上未经测试.
研究的目的:
- 在定期的NMR屏蔽计算中评估rSCAN函数的性能.
- 评估单体校正和双混合功能对屏蔽预测准确性的影响.
- 确定最佳的计算方法,以准确地预测分子固体中的13C化学转移.
主要方法:
- 使用rSCAN,PBE和BLYP优化的几何形状上使用rSCAN和PBE函数计算的NMR屏蔽.
- 应用了对计算的屏蔽进行的单体正.
- 研究了使用双混合函数 (mPW2PLYP) 与隐性溶解模型 (CPCM) 进行单体校正的方法.
主要成果:
- rSCAN提供了略有改进的几何形状,但化学转移的准确性不如最初的PBE.
- 经过单体校正的rSCAN性能优于经过校正的PBE,表明更好地描述了远程屏蔽贡献.
- 在rSCAN优化几何形状上的rSCAN周期计算中应用的mPW2PLYP-CPCM校正在一个大数据集上实现了前所未有的精度 (0.8ppm RMSE,0.6ppm MAE).
结论:
- 当rSCAN功能与单体校正和双混合功能 (mPW2PLYP-CPCM) 相结合时,可以显著提高周期性NMR屏蔽计算的准确性.
- 这种优化的方法为分子固体提供了高度可靠的13C化学转移预测,推进了NMR结晶学.
- 该研究强调了高级函数和校正方案对于固态NMR中准确的计算预测的重要性.
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