Using Density Matrix Quantum Monte Carlo for Calculating Exact-on-Average Energies for ab Initio Hamiltonians in a Finite Basis Set.,Journal of Chemical Theory and Computation

当前位置： X-MOL 学术 › J. Chem. Theory Comput. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Using Density Matrix Quantum Monte Carlo for Calculating Exact-on-Average Energies for ab Initio Hamiltonians in a Finite Basis Set.
Journal of Chemical Theory and Computation ( IF 5.7 ) Pub Date : 2020-01-28 , DOI: 10.1021/acs.jctc.9b01080
Hayley R Petras , Sai Kumar Ramadugu , Fionn D Malone ₁ , James J Shepherd

Affiliation

We here apply the recently developed initiator density matrix quantum Monte Carlo (i-DMQMC) to a variety of atoms and molecules in vacuum. i-DMQMC samples the exact density matrix of a Hamiltonian at finite temperature and combines the accuracy of full configuration interaction quantum Monte Carlo (FCIQMC)-full configuration interaction (FCI) or exact energies in a finite basis set-with finite temperature. In order to explore the applicability of i-DMQMC for molecular systems, we choose to study a recently developed test set by Rubenstein and co-workers: Be, H2O, and H10 at near-equilibrium and stretched geometries. We find that, for Be and H2O, i-DMQMC delivers energies with submillihartree accuracy when compared with finite temperature FCI. For H2O and both geometries of H10, we examine the difference between FT-AFQMC and i-DMQMC, which, in turn, estimates the difference in canonical versus grand canonical energies. We close with two discussions: one of simulation settings (initiator error, the interaction picture, and different basis sets), and another of energy difference calculations in the form of specific heat capacity and ionization potential calculations.

中文翻译：

使用密度矩阵量子蒙特卡罗方法计算有限基集合中从头算哈密顿量的平均平均能量。

在这里，我们将最近开发的引发剂密度矩阵量子蒙特卡罗（i-DMQMC）应用到真空中的各种原子和分子。i-DMQMC在有限温度下对哈密顿量的精确密度矩阵进行采样，并将完全构型相互作用量子蒙特卡罗（FCIQMC）-完全构型相互作用（FCI）或精确能量的精确性与有限温度下的有限基集相结合。为了探索i-DMQMC在分子系统中的适用性，我们选择研究由Rubenstein和他的同事最近开发的测试装置：Be，H2O和H10，处于近似平衡和扩展的几何形状。我们发现，对于Be和H2O，与有限温度FCI相比，i-DMQMC提供的能量具有毫毫hartreetree精度。对于H2O和H10的两个几何形状，我们检查了FT-AFQMC和i-DMQMC之间的差异，进而，估计正则能量与正则能量之差。我们以两个讨论结束：一个是模拟设置（引发剂误差，相互作用图和不同的基础集），另一个是以比热容和电离势计算形式的能量差计算。

更新日期：2020-01-29

点击分享查看原文

点击收藏

公开下载

阅读更多本刊最新论文本刊介绍/投稿指南11