DOI: 10.5281/zenodo.16700862
title: Data Set for the Development and Testing of the MC25 Meta Pair-Density Functional

description: This dataset contains files used to optimize and test the Multi-Configuration 25 (MC25) on-top pair-density functional and to compare the results obtained with this functional to results obtained with other methods. It includes files to carry out electronic structure calculations. These include OpenMolcas CASSCF wave function files, OpenMolcas basis set files, and PySCF checkpoint files. It also includes data used for data processing such as stoichiometries, absolute energies, and reference energies. A description of the content of each file can be found in the technical info section below.
description: Most files in this data repository are .tar.xz archives. One can extract them by the following command:

tar -xJf name_of_archive.tar.xz

openmolcas_basis_set.tar.xz contains OpenMolcas basis set files used for multireference calculations. To reproduce the results in this work, the basis set files should be placed in the “basis_library” directory in the OpenMolcas installation location.

database_name_table.txt is a text file listing the internal names of each database. Internal names are used in all the files listed below. For example, the MR-MGN-BE8 database has an internal name DS2_MR-MGN-BE. In all the descriptions below, the symbol database represents the internal name of each database rather than its formal name as appeared in the MC25 paper.

openmolcas_wave_function.tar.xz contains files needed by OpenMolcas to reproduce the CASSCF wave function used in this work. The files in the archive are named database/system.*.



The file system.xyz contains the Cartesian coordinates, which are generally provided in Å. In certain special cases, the coordinates are given in atomic units; these files have “bohr” specified on the second line. Note that for Data Set 2 (databases with internal name prefix DS2_), the coordinates are in the input files system.inp.

The file system.inp contains the OpenMolcas input file to perform CASSCF calculations.

The files system.RasOrb, system.rasscf.h5, and system.rasscf.molden contain the converged CASSCF natural orbitals. The files system.rasscf.h5 also includes the CI vectors.


pyscf_wave_function.tar.xz contains PySCF checkpoint files to reproduce the CASSCF wave function used in this work. The files in the archive are named database/system.chk. The molecules can be loaded from the checkpoint file using pyscf.lib.chkfile.load_mol(). Note that this function will also set the basis set to the one used in this work. The CASSCF molecular orbital coefficients can be accessed using the key “mcscf/mo_coeff”. The CI coefficients can be accessed using the key “mcscf/ci/state”, where state is an integer index representing the state being calculated. The ground state has a state index of 0. Additional information can be retrieved using the “metadata” and “energies” keys, which are stored as JSON texts that can be parsed using either json or pandas package. Some useful information stored in the two data sets includes the CASSCF energies, active space sizes, spin quantum numbers of each state, and irreps of each state. The “metadata” and “energies” data sets use a similar data structure to the one used by King et al. for the QUESTDB database. The checkpoint files for the QUESTDB database are converted from the pickle files provided by King et al. Please ignore the “grid_level” datum in the “metadata” data set as it was not used in the calculation of this work. We used grids_level = 5 for all MC-PDFT calculations performed in PySCF.

stoichiometry_energy.tar.xz contains files used for data processing.



Files with names like database.ref contain information used to calculate the final energies and errors. They are tab-delimited files. Each row represents an energy difference (e.g. atomization energy, barrier height, excitation energy etc.). The first column contains the name of the energy difference (note: spaces may be present in this column). This is followed by the file names of each electronic structure calculation and the stoichiometries used to calculate the energy difference from the absolute energies. Each name or stoichiometry occupies one column. For multistate calculations, an integer index representing the state being calculated is appended to the file name, separated by a slash (/). The ground state has an index of 0. The second from the last column contains the reference value. The reference values are in kcal/mol for ground-state databases and are in eV for excitation-energy databases. The units of the reference values are identified through the conversion factor from atomic units “!scale 627.5095” (kcal/mol) or “!scale 27.21139” (eV) given in the first line of each file. The reference values contain spin–orbit coupling. The last column contains the factor by which the final energy should be divided. This factor usually equals 1, but it can be greater than 1 for databases calculating atomization energies per bond or per atom.

Files with names like method.elist contain the absolute energies of each electronic structure calculation. They are tab-delimited files. Each row represents an electronic structure calculation, and each row always contains two columns. The first column is the file name of the calculation in the format database/system. For multistate calculations, the first column is in the format database/system/state, where state is an integer index representing the state being calculated. The ground state has a state index of 0. The second column is the absolute energy in atomic units extracted from the output file of electronic structure programs.

The file named SOC.dat contains the spin–orbit coupling term in kcal/mol to be added to each electronic structure calculation prior to calculating energy differences. It has the same format as files with names like method.elist.