Fu Bina, Xu Xin, Zhang Dong H
State Key Laboratory of Molecular Reaction Dynamics and Center for Theoretical and Computational Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People's Republic of China.
J Chem Phys. 2008 Jul 7;129(1):011103. doi: 10.1063/1.2955729.
We present a hierarchical construction scheme for accurate ab initio potential energy surface generation. The scheme is based on the observation that when molecular configuration changes, the variation in the potential energy difference between different ab initio methods is much smaller than the variation for potential energy itself. This means that it is easier to numerically represent energy difference to achieve a desired accuracy. Because the computational cost for ab initio calculations increases very rapidly with the accuracy, one can gain substantial saving in computational time by constructing a high accurate potential energy surface as a sum of a low accurate surface based on extensive ab initio data points and an energy difference surface for high and low accuracy ab initio methods based on much fewer data points. The new scheme was applied to construct an accurate ground potential energy surface for the FH(2) system using the coupled-cluster method and a very large basis set. The constructed potential energy surface is found to be more accurate on describing the resonance states in the FH(2) and FHD systems than the existing surfaces.
我们提出了一种用于精确从头算势能面生成的分层构建方案。该方案基于这样的观察结果：当分子构型发生变化时，不同从头算方法之间势能差的变化远小于势能本身的变化。这意味着在数值上表示能量差以达到所需精度更容易。由于从头算计算的计算成本随着精度的提高而迅速增加，通过构建一个高精度的势能面，作为基于大量从头算数据点的低精度表面与基于少得多的数据点的高低精度从头算方法的能量差表面之和，可以在计算时间上大幅节省。新方案被应用于使用耦合簇方法和非常大的基组为FH(2)系统构建精确的基态势能面。结果发现，构建的势能面在描述FH(2)和FHD系统中的共振态方面比现有表面更准确。
