Dataset pertaining to the article "How does Mg2+(aq) interact with ATP(aq)? Biomolecular Structure through the Lens of Liquid-Jet Photoemission Spectroscopy", published in Journal of the American Chemical Society (doi: 10.1021/jacs.4c03174). Here, we arrive at new information on the interaction of ATP with Mg under physiological conditions by interpreting photoelectron spectra and intermolecular Coulombic decay from a liquid microjet. Files with extension .h5 are hdf5-files structured according to the NeXus standard v2022.07, seehttps://www.nexusformat.org/https://fairmat-experimental.github.io/nexus-fairmat-proposal/50433d9039b3f33299bab338998acb5335cd8951/mpes-structure.htmlNeXus data files can be opened with any software capable of opening hdf5-structured files. The following viewers are adapted to the specifics of the NeXus data format:* nexpy (distributed with python)* https://h5web.panosc.eu/h5wasm (web-based NeXus viewer maintained by the European Photon and Neutron Open Science Cloud-consortium) In each NeXus file-entry, two types of spectra are shown:1. Sweep-averaged spectra, integrated over the non-dispersive coordinate of our detector ('data'). For ATP spectra, the ADP overview spectrum, and ADP/Mg2+ Mg 2s spectra, a binding energy correction shifting the liquid 1b1 feature to 11.33 eV is applied.2. As-measured data ('raw'). Files with extension .txt are comma-separated ascii-files. The following files are provided: Photoemission data pertaining to adenosine phosphate PES measurements:atp-mg.h5 - ATP photoemission spectra in the presence of Mg2+ cations in varying concentrationadp-mg.h5 - ADP photoemission spectra in the presence of Mg2+ cations in varying concentrationamp-mg.h5 - AMP photoemission spectra in the presence of Mg2+ cations (a single concentration)atp-adp-amp.h5 - ATP, ADP, AMP photoemission without Mg admixturemg-only.h5 - Mg 2s core level spectra without ATPtham-only.h5 - VB band measured with only THAM (tris(hydroxymethyl)aminomethane), used as buffer for pH stabilizationatp-icd.h5 - ATP photoemission spectra in the presence of Mg2+ cations, kinetic energy range of ICD features (publication is based on the last three entries). Numeric representations of the traces shown in the article's figures:Figure_3-data.txtFigure_5a-Mg2p.txtFigure_5a-Mg2s.txtFigure_5a-Mgonly.txtFigure_5a-P2p.txtFigure_5a-P2s.txtFigure_5b.txtFigure_5c.txtFigure_6-ADP.txtFigure_6-AMP.txtFigure_6-ATP.txtFigure_8a-data.txtFigure_S2-Tris.txtFigure_S2-Tris_with_Mg2+.txtFigure_S4-data.txt. Version history3: updated to reflect changes in Figure numbering between ArXiv-post and version published in JACS, additional Figure 5-data added2: NeXus-data added1: initial upload Contact person for questions regarding this data set: Uwe Hergenhahn, uhe@fhi.mpg.de . If you use these data for your scientific work we are curious to learn about it.

Funding acknowledgements: C.L. was supported by the Director of the Office of Basic Energy Science, Chemical Sciences Division of the US Department of Energy under contract number DE-AC02-05CH11231 and the Alexander von Humboldt Foundation. L.T. and P.S. acknowledge the support of the Czech Science Foundation, project number 21-26601X (EXPRO project). S. B. acknowledges NSF CHE-0617060 for early phases of this work and NSF CHE-1665532 for travel support in finalizing the work. B. W. acknowledges funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and investigation programme (grant agreement No. 883759). The authors would like to thank Robert Seidel, Christi Schroeder, Anne B. Stephansen, Claudia Kolbeck, Marvin Pohl, Iain Wilkinson and Gerard Meijer for their support along different stages of the project and during initial experiments at BESSY II.