predicted correctly. Due to the poor prediction of harmonic frequencies, carbon–fluorine stretching vibrations are often strongly misplaced by common hybrid functionals such as B3LYP. Herein we show that the M06-2X functional provides harmonic C–F stretching frequencies with an accuracy sufficient for a reliable spectra analysis. We briefly discuss the origin of this exceptional performance and show that
振动圆二色性和红外光谱的分析通常需要在密度泛函理论
水平上预测光谱。特别是对于绝对配置确定(通常由相似性分析算法支持实验和理论之间的比较),重要的是正确预测频率,相对谱带强度和
VCD符号。由于对谐波频率的预测不佳,碳-
氟拉伸振动通常会被常见的混合功能(例如B3LYP)严重放错位置。本文中,我们证明了M06-2X功能可提供谐波CF拉伸频率,其准确度足以进行可靠的频谱分析。我们简要讨论了这种出色性能的起源,并表明它可能与消除错误有关。