Revisiting the Maximum Hardness Principle: A Quantitative Analysis on Reaction Datasets

This Zenodo repository contains the data presented in A. Bajaj, F. Heidar-Zadeh, T. Stuyver, S. Habershon, P. W. Ayers, F. De Proft, "Revisiting the Maximum Hardness Principle: A Quantitative Analysis on Reaction Datasets", Journal of Computational Chemistry (2026): e70365, https://doi.org/10.1002/jcc.70365. The dataset included here primarily contains the electronic structure calculations for N+1 and N-1 electronic states of all molecules contained in the existing BH9 dataset. The BH9 dataset (J. Chem. Theory Comput. 2022, 18, 1, 151–166) contains 449 chemical reactions belonging to nine different reaction types. The original dataset comes with the plain text db files for 449 reactions, xyz files for 1775 molecular structures involving reactants, products and transition states optimized at CAM-B3LYP-D3(BJ)/6-311++G** level of theory along with the computed reaction energies, forward and reverse barrier heights of 449 reactions. In this repository we provide gaussian log files for single-point calculations performed for N, N+1 and N-1 electron species at (U)BLYP-D3(BJ)/6-311++G* level at optimized geometries taken from BH9 dataset. We recommend people to refer this dataset as BH9-ΔN i.e. ionization extension of BH9 dataset which includes electronic structure calculations for N+1 and N-1 electronic states of all molecules in BH9 dataset. We also provide the gaussian log files for N-electron calculations re-performed using unrestricted (U)CAM-B3LYP-D3(BJ)/6-311++G** level of theory. The raw log-files for all the calculations are stored in BH9_UBLYP_deltaN.tar.gz and BH9_UCAMB3LYP_N.tar.gz. BH9_UBLYP_deltaN.tar.gz contains separate folder for N, N+1 and N-1 electronic structure calculations, each of which contains log files for 1775 molecular structures belonging to reactants, products and transition states of 449 reactions. Total Energies for N, N+1 and N-1 electron systems along with computed ionization potential and electron affinities at (U)BLYP-D3(BJ)/6-311++G* level for 1775 molecules can be found in bh9_UBLYP_IPEA.csv. Negative affinites have been corrected with Tozer-De-Proft (TDP) approximation and are also included as well. The list of conceptual DFT global reacitivity descriptors including chemical potential (mu), electronegativity (chi), hardness (eta), softness (soft) and electrophilicity (omega) computed in finite difference approximation and corrected with TDP approximation at (U)BLYP-D3(BJ)/6-311++G* level of theory are provided in bh9_cdft_FDA_UBLYP.csv. N-electron orbital energies and reactivity descriptors computed using frontier molecular approximation (FMA) at (U)BLYP-D3(BJ)/6-311++G and (U)CAM-B3LYP-D3(BJ)/6-311++G are provided in bh9_cdft_FMA_UBLYP.csv and bh9_cdft_FMA_UCAMB3LYP.csv, respectively. All the energies and computed descriptors are provided in eV unless stated otherwise.