Benchmarking study on time-dependent density functional theory calculations of electronic circular dichroism for gas-phase molecules
Benchmarking study on time-dependent density functional theory calculations of electronic circular dichroism for gas-phase molecules
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DOI：
10.1016/j.comptc.2018.01.003
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发表时间：
2018-02-01
影响因子：
2.8
通讯作者：
Heo, Jiyoung
中科院分区：
文献类型：
--
作者：
Jang, Heeseon;Kim, Nam Joon;Heo, Jiyoung
含时密度泛函(TDDFT)理论已成为计算电子激发态的常用方法。用TDDFT方法可以计算手性分子的电子圆二色谱(ECD)来解析它们的绝对构型。在这项工作中，我们评估了TDDFT计算三个手性分子的ECD的性能，这些分子的振动CD谱最近被报道在超音速喷流中。我们测试了7种不同的泛函(PBEPBE、PBE1PBE、B3LYP、mPW1PW91、M06-2X、CAM-B3LYP和omega B97X-D)在不同的Pople基组水平下，预测了手性分子的垂直和绝热激发的转动强度。6-311++G(d，p)基组适用于ECD计算，扩散函数的增加提高了基组在计算旋转强度时的质量。在笛卡尔坐标下绝热Hessian格式下振动CD谱的模拟只适用于M06-2X、CAM-B3LYP和Omega B97X-D泛函。(1R，2S)-麻黄碱和(S)-2-氨基-1-苯乙醇的0-0跃迁的旋光强度信号与实验结果吻合较好。对于(15，2S)-伪麻黄碱构象，用这三种泛函预测的旋光强度信号是一致的，但与实验结果不一致。对于TDDFT中的几何优化，PBEPBE和B3LYP泛函是不稳健的，因为使用这些泛函的计算不能为S-1状态下的某些构象提供合理的平衡几何构型。通过与构象特定CD谱的比较，明确评估了适用于ECD计算的DFT泛函。(C)2018爱思唯尔B.V.保留所有权利。
Time-dependent density functional (TDDFT) theory has become a popular method to calculate electronic excited states. The electronic circular dichroism (ECD) spectra of chiral molecules can be computed by TDDFT to resolve their absolute configurations. In this work, we evaluated the performance of TDDFT to calculate ECD of three chiral molecules whose vibronic CD spectra in a supersonic jet were recently reported. We tested seven different functionals (PBEPBE, PBE1PBE, B3LYP, mPW1PW91, M06-2X, CAM-B3LYP, and omega B97X-D) with different levels of the Pople basis set to predict the rotatory strengths of both vertical and adiabatic excitations of the chiral molecules. The 6-311++G(d,p) basis set is appropriate for the ECD calculation, and the augmentation of the diffuse function improves the quality of basis set in calculating the rotatory strength. The simulations of vibronic CD spectra under the adiabatic Hessian scheme in Cartesian coordinates have been feasible only with the M06-2X, CAM-B3LYP, and omega B97X-D functionals. The rotatory strength signs for the 0-0 transition of (1R, 2S)-ephedrine and (S)-2-amino-1-phenylethanol agree well with the experimental results. For the (15, 2S)-pseudoephedrine conformers, the rotatory strength signs predicted using those three functionals are consistent with each other but do not coincide with the experimental results. The PBEPBE and B3LYP functionals are not robust for geometry optimizations in TDDFT because the calculations using these functionals do not provide reasonable equilibrium geometries for some conformers in the S-1 state. Comparison with the conformation specific CD spectra provides the unambiguous assessment of the DFT functionals suitable for ECD calculations. (C) 2018 Elsevier B.V. All rights reserved.