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arXiv 1806.05068physics.chem-phcond-mat.stat-mech
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工业催化剂的量子蒙特卡罗先决条件。准确估算H原子和H $_2$在Pt(111)上的物理吸附能

Quantum Monte Carlo prerequisites for industrial catalysts. Accurately assessing H atom and H$_2$ physical adsorption energy on Pt(111)

Philip E. Hoggan

摘要:

与可靠的实验相比,新的第一性原理方法对金属表面反应路径上关键点的衡量标准是化学准确性。这意味着活化势垒的值需要在1 kcal/mol以内。量子蒙特卡罗(QMC)是一个有前途的(虽然冗长)的第一性原理方法,我们现在已经超越了这些系统的QMC基准的曙光,因为在两个改进的QMC研究\cite{hog0, kdd2}中已经研究了Cu(111)上的氢解离,具有相当足够的精度。铂和铜需要使用的赝势在这些计算中,我们表明,那些铂的问题比那些铜,特别是QMC工作。本文测定了氢原子和氢分子在Pt(111)表面的物理吸附能。这些系统被用来作为渐近线,以确定反应障碍。因此,它们必须涉及干净的Pt(111)表面和孤立的氢原子或分子。以前的工作给出了氢在Pt(111)上解离的活化能垒。所用方法为最新技术水平({ \it ab initio})QMC。该屏障与最近的特定反应参数(SRP-DFT)计算(适合测量值\cite{iran})的化学准确性一致。结果给出氢在Pt(111)上的解离势垒为5.4 kcal/mol(QMC和6.2,通过SRP-DFT),QMC标准误差低于0.99 kcal/mol。这对于在Pt(111)上建立不太知名的工业反应势垒基准值是令人鼓舞的。

英文摘要:

The yardstick of new first-principles approaches to key points on reaction paths at metal surfaces is chemical accuracy compared to reliable experiment. By this we mean that such values as the activation barrier are required to within 1 kcal/mol. Quantum Monte Carlo (QMC) is a promising (albeit lengthy) first-principles method for this and we are now beyond the dawn of QMC benchmarks for these systems, since hydrogen dissociation on Cu(111) has been studied with quite adequate accuracy in two improving QMC studies \cite{hog0, kdd2}. Pt and Cu require the use of pseudo-potentials in these calculations and we show that those of Pt are less problematic than those for Cu, particularly for QMC work. This work determines physisorption energies for hydrogen atoms and molecules on Pt(111). These systems are used as asymptotes to determine reaction barriers. As such, they must be referred to clean Pt(111) surfaces and the isolated hydrogen atom or molecule. Previous work gave the activation barrier to hydrogen dissociation on Pt(111) using the bridging geometry. The method used is state-of-the-art ({\it ab initio}) QMC. This barrier agrees to better than chemical accuracy with a recent Specific Reaction Parameter (SRP-DFT) calculation, fitted to measurement \cite{iran}. The results give the dissociation barrier for hydrogen on Pt(111) as 5.4 kcal/mol (QMC and 6.2 by SRP-DFT) with a QMC standard error below 0.99 kcal/mol. This is encouraging for establishing less well-known benchmark values of industrial reaction barriers on Pt(111).

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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