论文标题
全构型相互作用量子卡洛的一般分析核力量和分子势能表面
General analytical nuclear force and molecular potential energy surface from full configuration interaction quantum Monte Carlo
论文作者
论文摘要
完整的配置相互作用量子蒙特卡洛（FCIQMC）是一种最新的随机电子结构方法，它提供了一种在量子化学基础内计算分子系统的FCI级态能量的方法。但是，尤其是在FCIQMC水平上探测{\ em Dynamics}，有必要设计出更有效的方案来从FCIQMC产生核力量和势能表面（PES）。在这项工作中，我们从FCIQMC得出了核力量的一般公式，并阐明了总力的不同贡献。这种获得FCIQMC力的方法消除了先前的限制，并且可以与冷冻的核心近似和自由选择轨道一起使用，从而使其有望获得更有效的核力量计算。在数值检查该过程的N $ _2 $分子的结合曲线上后，我们使用FCIQMC能量和力通过高斯工艺回归来获得水分子的全维基态PES。新的水FCIQMC PEs可以用作基础状态核动力学，结构优化和旋转振动频谱计算的基础。
Full configuration interaction quantum Monte Carlo (FCIQMC) is a state-of-the-art stochastic electronic structure method, providing a methodology to compute FCI-level state energies of molecular systems within a quantum chemical basis. However, especially to probe {\em dynamics} at the FCIQMC level, it is necessary to devise more efficient schemes to produce nuclear forces and potential energy surfaces (PES) from FCIQMC. In this work, we derive the general formula for nuclear force from FCIQMC, and clarify different contributions of the total force. This method to obtain FCIQMC forces eliminates previous restrictions, and can be used with frozen core approximation and free selection of orbitals, making it promising for more efficient nuclear force calculations. After numerical check of this procedure on the binding curve of N$_2$ molecule, we use the FCIQMC energy and force to obtain the full-dimensional ground state PES of water molecule via Gaussian processes regression. The new water FCIQMC PES can be used as the basis for H$_2$O ground state nuclear dynamics, structure optimization, and rotation-vibrational spectrum calculation.
