Chen Junbo, Chan Bun, Shao Yihan, Ho Junming
School of Chemistry, University of New South Wales, Sydney, NSW 2052, Australia.
Graduate School of Engineering, Nagasaki University, Bunkyo-Machi 1-14, Nagasaki 852-8521, Japan.
Phys Chem Chem Phys. 2020 Feb 19;22(7):3855-3866. doi: 10.1039/c9cp06792b.
In this paper, the performance of a wide range of DFT methods is assessed for the calculation of interaction energies of thermal clusters of a solute in water. Three different charge states (neutral, proton transfer transition state and zwitterion) of glycine were solvated by 1 to 40 water molecules as sampled from molecular dynamics simulations. While some ab initio composite methods that employ insufficiently large basis sets incurred significant errors even for a cluster containing only 5 water molecules relative to the W1X-2 benchmark, the DLPNO-CCSD(T)/CBS and DSD-PBEP86 (triple zeta basis set) levels of theory predicted very accurate interaction energies. These levels of theory were used to benchmark the performance of 16 density functionals from different rungs of Jacob's Ladder. Of the Rung 4 functionals examined, the ωB97M-V and ωB97X-V functionals stood out for predicting absolute interaction energies in 40-water clusters with mean absolute deviations (MAD) ∼4 kJ mol-1. The B3LYP-D3(BJ) functional performed exceptionally well with a MAD ∼1.7 kJ mol-1 and is the overall best performing method. Calculations of relative interaction energies allow for cancellation of systematic errors, including basis set truncation and superposition errors, and the ωB97M-V and B3LYP-D3(BJ) double zeta basis set calculations yielded relative interaction energies that are within ∼3 kJ mol-1 of the benchmark. The ONIOM approximation provides another strategy for accelerating the calculation of accurate absolute interaction energies provided that the calculations have converged with respect to the size of the "high-level-layer".
在本文中，评估了多种密度泛函理论（DFT）方法用于计算水中溶质热团簇相互作用能的性能。甘氨酸的三种不同电荷状态（中性、质子转移过渡态和两性离子）被1至40个水分子溶剂化，这些水分子是从分子动力学模拟中采样得到的。虽然一些使用的基组不够大的从头算复合方法，即使对于仅包含5个水分子的团簇，相对于W1X - 2基准也会产生显著误差，但DLPNO - CCSD(T)/CBS和DSD - PBEP86（三重ζ基组）理论水平预测了非常准确的相互作用能。这些理论水平被用于评估来自雅各布天梯不同阶梯的16种密度泛函的性能。在所研究的第4阶梯密度泛函中，ωB97M - V和ωB97X - V泛函在预测40 - 水分子团簇的绝对相互作用能方面表现突出，平均绝对偏差（MAD）约为4 kJ mol⁻¹。B3LYP - D3(BJ)泛函表现异常出色，MAD约为1.7 kJ mol⁻¹，是整体表现最佳的方法。相对相互作用能的计算允许消除系统误差，包括基组截断和叠加误差，并且ωB97M - V和B3LYP - D3(BJ)双ζ基组计算得到的相对相互作用能与基准值相差约3 kJ mol⁻¹以内。只要计算在“高层级层”的大小方面已经收敛，ONIOM近似为加速准确绝对相互作用能的计算提供了另一种策略。
