1. ABOUT THE DATASET
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Title: Dataset supporting the article 'Core-level binding energies describe electrostatic potentials at nuclei for ionic liquids'

Creator(s): Frances K. Towers Tompkins[1] orcid.org/0009-0009-9882-1301, Ricardo Grau-Crespo[2] orcid.org/0000-0001-8845-1719, and Kevin R. J. Lovelock[1] orcid.org/0000-0003-1431-269X.

Organisation(s): [1] Department of Chemistry, University of Reading, Reading RG6 6DX, U.K. 
				 [2] School of Engineering and Materials Science, Queen Mary University of London, Mile End Rd., London E1 4NS, U.K. 

Rights-holder(s): Frances K. Towers Tompkins, Queen Mary University of London and University of Reading.

Publication Year: 2025

Description: This compressed file is supplementary to the article cited in the 'Related publication' section below. Its contents include the input and (some) output files of the ionic liquid [C8C1Im][TfO] studied here computationally. These computational files will allow you to replicate both the Ab Initio Molecular Dynamics (MD)
(calculated using CP2K) and the Density Functional Theory (DFT) (calculated using VASP) calculations shown in the article. All XPS experimental data is previously published (as referenced in CONTENTS) and the data for the three other ILs studied computationally is already published as follows: F. K. Towers Tompkins, R. Grau-Crespo and K. R. J. Lovelock, 2024: Dataset supporting the article
'Anion-dependent strength scale of interactions in ionic liquids from x-ray photoelectron spectroscopy, ab initio molecular dynamics, and density functional theory'. University of Reading. Dataset. https://doi.org/10.17864/1947.001317

Cite as: F. K. Towers Tompkins, R. Grau-Crespo and K. R. J. Lovelock, 2025: Dataset supporting the article
'Core-level binding energies describe electrostatic potentials at nuclei for ionic liquids'. University of Reading. Dataset. DOI: 10.17864/1947.001453

Related publication: Towers Tompkins, F. K., Gousseva, E., Bennett, R. A., Grau-Crespo, R. and Lovelock, K. R. J. (2025) Core-level binding energies describe electrostatic potentials at nuclei for ionic liquids. Physical Chemistry Chemical Physics, 27 (41). pp. 22004-22012. ISSN 1463-9084 doi: 10.1039/d5cp02411k

Contact: Kevin R. J. Lovelock (k.r.j.lovelock@reading.ac.uk)

2. TERMS OF USE
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Copyright 2025 Frances Towers Tompkins, Queen Mary University of London, and University of Reading. This dataset is licensed under a Creative Commons Attribution 4.0 International Licence:
https://creativecommons.org/licenses/by/4.0/.


3. PROJECT AND FUNDING INFORMATION
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Title: The Materials and Molecular Modelling Hub
Dates: Jan. 2020 - Mar. 2026
Funding organisation: EPSRC
Grant no.: EP/T022213/1

Title: High End Computing Materials Chemistry Consortium
Dates: Nov. 2018 - Dec. 2022
Funding organisation: EPSRC
Grant no.: EP/R029431/1

Title: X-ray Spectroscopy of Liquids: Quantifying Lewis Reactivity
Dates: Feb. 2019 - Jan. 2023
Funding organisation: The Royal Society
Grant no.: URF\R\150353

Title: Quantifying Ion-Solvent Interactions Using X-Ray Photoelectron Spectroscopy
Dates: Apr. 2022 - Mar. 2025
Funding organisation: The Royal Society
Grant no.: URF\R\211005

Title: Electronic Structure of Liquid Phase Metal Complexes
Dates: Jan. 2018 - Mar. 2025
Funding organisation: The Royal Society
Grant no.: RGF\EA\180089

Title: Understanding Ionic Liquid Electrochemical Stability: Towards Superior Electrochemical Devices
Dates: Oct. 2016 - Mar. 2022
Funding organisation: The Royal Society
Grant no.: RGF\R1\180053

Title: Quantifying Ion-Solvent Interactions Using X-Ray Photoelectron Spectroscopy
Dates: Dec. 2021 - Mar. 2025
Funding organisation: The Royal Society Research Fellows Enhanced Research Expenses 2021
Grant no.: RF\ERE\210061

Title: Quantifying Ion-Solvent Interactions Using X-Ray Photoelectron Spectroscopy
Dates: Jun. 2023 - Mar. 2025
Funding organisation: The Royal Society Research Fellows Enhanced Research Expenses 2023
Grant no.: RF\ERE\231015


4. CONTENTS
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All experimental XPS for [C8C1Im]Cl, [C8C1Im][SCN] and [C8C1Im][NTf2] and [C8C1Im][TfO] were included in the ESI of a previous publication: R. M. Fogarty, R. G. Palgrave, R. A. Bourne, K. Handrup, I. J. Villar-Garcia, D. J. Payne, P. A. Hunt and K. R. J. Lovelock, Phys. Chem. Chem. Phys., 2019, 21, 18893-18910 DOI: doi.org/10.1039/C9CP02200G

This dataset includes only previously unpublished computational data.

File listing

-------- '~/1.calculations'
This directory is further organised into two directories: '~/1.calculations/1.1.cp2k' and '~/1.calculations/1.2.vasp'.

------ '~/1.calculations/1.1.cp2k'

This directory contains the CP2K input files that were required for structural equilibration of the ionic liquid [C8C1Im][TfO] studied computationally in the article cited in section 1.

	1. 'BASIS_MOLOPT' --> Library of molecularly optimised basis functions, obtained from J. VandeVondele and J. Hutter, J. Phys. Chem., 127, 114105 (2007) DOI: https://doi.org/10.1063/1.2770708
	2. 'cp2k_C8C1Im_TfO.inp' --> CP2K input file used for the ionic liquid C8C1Im TfO (1-Octyl-3-methylimidazolium Trifluoromethanesulfonate).
	3. 'GTH_POTENTIALS' --> Pseudopotential database.
	3. 'input_C8C1Im_TfO.cif' --> Input structure used for the ionic liquid C8C1Im TfO (1-Octyl-3-methylimidazolium Trifluoromethanesulfonate)in cif file format.
	
If wanted, an updated version of the basis sets (BASIS_MOLOPT) and pseudopotentials (GTH_POTENTIALS) can be obtained on the CP2K github webpage: https://github.com/cp2k/cp2k/tree/master/data
We have not included any submission scripts to run CP2K, as this is dependent on your machine. 

------ '~/1.calculations/1.2.vasp'

This directrory contains all the data needed for running Density Functional Theory (DFT) calculations using the Vienna Ab Initio Simulation Package (VASP) on the ionic liquid [C8C1Im][TfO] (1-Octyl-3-methylimidazolium Trifluoromethanesulfonate) studied computationally in the article cited in section 1, to obtain (1) initial state core energies and (2) electrostatic site potentials.

This directory contains the following:

	
	
	1. 'INCAR_C8C1Im_TfO_CL' --> Plain text input file used for the ionic liquid C8C1Im SCN (1-Octyl-3-methylimidazolium Thiocyanate).
	2. 'INCAR_C8C1Im_TfO_ESP' --> Plain text input file used for the ionic liquid [C8C1Im][TfO] (1-Octyl-3-methylimidazolium Trifluoromethanesulfonate).
	3. 'KPOINTS' --> Plain text file used to sample the Brillouin zone. This file was the same for all calculations of all three ionic liquids.
	4. 'OUTCAR_C8C1Im_TfO_CL' --> Plain text output file obtained for the ionic liquid [C8C1Im][TfO] (1-Octyl-3-methylimidazolium Trifluoromethanesulfonate).
	5. 'OUTCAR_C8C1Im_TfO_ESP' --> Plain text output file obtained for the ionic liquid [C8C1Im][TfO] (1-Octyl-3-methylimidazolium Trifluoromethanesulfonate).
    6. 'POSCAR' --> Plain text file containing the lattice geometry and the ionic poistions of the ionic liquid [C8C1Im][TfO] (1-Octyl-3-methylimidazolium Trifluoromethanesulfonate).

We have only included one configuration of each ionic liquid (of average energy), as opposed to the three studied of each in the article. More configurations can be obtained from the output files of your own CP2K calculations.

The core energies for each atom can be obtained from the OUTCAR (labelled 'OUTCAR_C8C1Im_TfO_CL'). More information can be found here: https://www.vasp.at/wiki/index.php/ICORELEVEL
The electrostatic site potentials for each atom can be obtained from the OUTCAR (labelled 'OUTCAR_C8C1Im_TfO_ESP').

The NCORE tag found in the INCAR, should be dependent on your machine. More information can be found here: https://www.vasp.at/wiki/index.php/NCORE

Remember, they are a minimum of five files needed to run a DFT calculation in VASP (INCAR, KPOINTS, POSCAR, POTCAR, and a submission script). Change the name of each INCAR and POSCAR file before submission.
We have not included the file that contains the pseudopotentials for each atomic species used in the calculation (POTCAR), due to licensing.
We have not included any submission scripts to run VASP, as this is dependent on your machine.
More information on running VASP calculations can be found on the VASP Manual, here:
https://www.vasp.at/wiki/index.php/The_VASP_Manual


5. METHODS
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All methods on how the X-ray photoelectron spectroscopy datasets were obtained as well as the methods and parameters used to run all calculations can be found in the article cited in section 1.
Any questions on the methods can be directed to Kevin R. J. Lovelock (k.r.j.lovelock@reading.ac.uk).
