** Reference to paper:

JCTC (1017)

** DOI:

10.1021/acs.jctc.7b00344

** Title:

Quantum Monte Carlo Calculations on a Benchmark Molecule−Metal Surface Reaction: H2 + Cu(111)

** Authors:

Katharina Doblhoff-Dier, Jörg Meyer, Philip E. Hoggan, and Geert-Jan Kroes

** Contact e-mail:

k.doblhoff-dier@umail.leidenuniv.nl
g.j.kroes@chem.leidenuniv.nl

** Abstract:

Accurate modeling of heterogeneous catalysis requires the availability of highly accurate potential energy surfaces. Within density functional theory, these can - unfortunately - depend heavily on the exchange-correlation functional. High-level ab initio calculations, on the other hand, are challenging due to the system size and the metallic character of the metal slab. Here, we present a quantum Monte Carlo (QMC) study for the benchmark system H2 + Cu(111),focusing on the dissociative chemisorption barrier height. These computationally extremely challenging ab initio calculations agree to within 1.6 ± 1.0 kcal/mol with a chemically accurate semiempirical value. Remaining errors, such as time-step errors and locality errors, are analyzed in detail in order to assess the reliability of the results. The benchmark studies presented here are at the cutting edge of what is computationally feasible at the present time. Illustrating not only the achievable accuracy but also the challenges arising within QMC in such a calculation, our study presents a clear picture of where we stand at the moment and which approaches might allow for even more accurate results in the future.

** Description per file:

** Folder pseudopotentials
Pseudopotentials used (in various different formats if applicable)
- 01-H.GGA_JM.pspconvert.fhi: hydrogen PP in fhi format  
- 01-H.GGA_JM.pspconvert.fhi_1s1.UPF: same as above converted to UPF format
- 01-H.GGA_JM.pspconvert.fhi.casinoTab: same as above converted to the format used in casino  
- 29-Cu.GGA_MF_s17.pspconvert.fhi: large core Cu PP in fhi format
- 29-Cu.GGA_MF_s17.pspconvert.fhi.UPF: large core Cu PP converted to UPF format
- 29-Cu.GGA_MF_s17.pspconvert.fhi.casinoTab: large core Cu PP converted to the format used in casino  
- Cu.upf: small core Cu PP in upf format
- Cu.local2.casinoTab: small core Cu PP converted to the format used in casino


** Folder manuscript:
Last tex version of the manuscript, figures in eps and where available in svg, bibliography (bib) and pdf (only available group-internally)


** Folder supplementray:
Last tex version of the supplementary material, bibliography (bib) and pdf (only available group-internally)


** Folder data_DFT-TestsSmallCoreCuPP:
Inputs, etc used for Table 1 and 2: 

The pseudopotentials referenced in the pwscf.in files can be found in the pseudopotential directory, with the following equivalences:
Cu_myPPs_V01.UPF -> Cu.upf
H_myPPs_V01.UPF -> 01-H.GGA_JM.pspconvert.fhi_1s1.UPF

- for table 1 see info files in folders cohesiveEnergy and equationOfState
Code used to fit equation of state (only available group-internally): see python script FitEquationOfState.py in subfolder equationOfState/FitEquationOfState
- for table 2: data from dir_00059, dir_00060


**Folder data_coverageTests:
Input files for convergence tests for coverage (used in supplementary). 
See info file in folder for more information on how information was extracted from the calculations.
The POTCAR file lies in the directory itself and was used in all subdirectories.


** Folder dmc_results:
These data where generated on cartesius (original folder name: Project_H2onCu111/runs_singePrecBlip_convThrs1E-16)
The analysis was done on my desktop (host 14)

The pseudopotentials referenced correspond to the the followingin pps in the pseudopotential directory:
Cu_jorg.casinoTab -> 29-Cu.GGA_MF_s17.pspconvert.fhi.casinoTab
Cu_myPPs_V01.casinoTab -> Cu.local2.casinoTab
H_jorg.casinoTab -> 01-H.GGA_JM.pspconvert.fhi.casinoTab
H_myPPs_V01.casinoTab -> 01-H.GGA_JM.pspconvert.fhi.casinoTab (i.e. same as H_jorg.casinoTab)

- jobDB.data: sqlite3 database containing the specifications of the run and the final results
- generatingPythonScripts: python scripts that can be used to automatically build the input from the database and get the results (only available group-internally)
- analysis_04.ipynb: jupyter notebook (version of the notebook server is 4.2.2 and is running on: Python 2.7.8)
- *.py files: contain methods needed by analysis_04.ipynb


** Folder sourceCodeChanges:
changes to the source code needed in pwscf from quantum espresso and in casino (only available group-internally)