Fixed-Node Diffusion Quantum Monte Carlo Method on Dissociation Energies and Their Trends for R-X Bonds (R = Me, Et, i-Pr, t-Bu)
Fixed-Node Diffusion Quantum Monte Carlo Method on Dissociation Energies and Their Trends for R-X Bonds (R = Me, Et, i-Pr, t-Bu)
复制标题
R-X 键解离能及其趋势的固定节点扩散量子蒙特卡罗方法（R = Me、Et、i-Pr、t-Bu）
DOI：
10.1021/acs.jpca.8b03149
复制
发表时间：
2018-06-07
影响因子：
2.9
通讯作者：
Wang, Fan
中科院分区：
文献类型：
--
作者：
Hou, Aigiang;Zhou, Xiaojun;Wang, Fan
Achieving both bond dissociation energies (BDEs) and their trends for the R-X bonds with R = Me, Et, i-Pr, and t-Bu reliably is nontrivial. Density functional theory (DFT) methods with traditional exchange-correlation functionals usually have large error on both the BDEs and their trends. The M06-2X functional gives rise to reliable BDEs, but the relative BDEs are determined not as accurately. More demanding approaches such as some double-hybrid functionals, for example, G4 and CCSD(T), are generally required to achieve the BDEs and their trends reliably. The fixed-node diffusion quantum Monte Carlo method (FN-DMC) is employed to calculated BDEs of these R-X bonds with X = H, CH3, OCH3, OH, and F in this work. The single Slater-Jastrow wave function is adopted as trial wave function, and pseudopotentials (PPs) developed for quantum Monte Carlo calculations are chosen. Error of these PPs is modest in wave function methods, while it is more pronounced in DFT calculations. Our results show that accuracy of BDEs with FN-DMC is similar to that of M06-2X and G4, and trends in BDEs are calculated more reliably than M06-2X. Both BDEs and trends in BDEs of these bonds are reproduced reasonably with FN-DMC. FN-DMC using PPs can thus be applied to BDEs and their trends of similar chemical bonds in larger molecules reliably and provide valuable information on properties of these molecules.
