XC100

XC100 is a dataset of 100 atomic and molecular systems containing wavefunction-derived exchange-correlation energies for the development and benchmarking of density functional approximations.

This repository accompanies ongoing work from the Zimmerman Group at the University of Michigan.

Repository contents

• XC100_dataset.csv — XC100 exchange-correlation dataset for systems 001–100.
• molecule_mapping.txt — mapping between the numerical system IDs and molecular/species names.
• XC100_structures.zip — molecular geometries for all 100 systems in XYZ format.
• CI_derived_KS_AO_density_matrices/ — CI-derived Kohn–Sham one-particle reduced density matrices (1-RDMs) in the cc-pVTZ AO basis for systems 001–100.

Dataset columns

Column	Description
System	Three-digit XC100 system identifier
Exc_TZ	Exchange-correlation energy at the cc-pVTZ level
TZ_correlation	cc-pVTZ correlation energy
QZ_correlation	cc-pVQZ correlation energy
CTZ_correlation	cc-pCVTZ correlation energy
delta_Riemann_QZ_to_CBS	Riemann-extrapolated correction from QZ to the complete-basis-set limit
Exc_comp	Final composite exchange-correlation energy
Ex_TZ	Exchange energy obtained from the cc-pVTZ inversion

All energies are reported in Hartree.

The Exc_comp values correspond to the final composite, Riemann-corrected exchange-correlation energies.

Structures and system IDs

Structures are provided as individual XYZ files named according to the XC100 system identifier:

001.xyz
002.xyz
...
100.xyz

The corresponding species names are provided in molecule_mapping.txt.

CI-derived Kohn–Sham 1-RDMs

The CI-derived Kohn–Sham one-particle reduced density matrix (1-RDM) for each XC100 system is provided in the cc-pVTZ AO basis. Each numbered subdirectory corresponds to the matching XC100 system identifier and contains a Paoks file.

Citation

If you use the XC100 dataset in your research, please cite:

Vaibhav Khanna and Paul M. Zimmerman,
XC100: A Wavefunction-Derived Exchange-Correlation Energy Dataset for Atomic and Molecular Species,
arXiv:2609.22490 [physics.chem-ph] (2026).

@misc{khanna2026xc100wavefunctionderivedexchangecorrelationenergy,
      title={XC100: A Wavefunction-Derived Exchange-Correlation Energy Dataset for Atomic and Molecular Species},
      author={Vaibhav Khanna and Paul M. Zimmerman},
      year={2026},
      eprint={2609.22490},
      archivePrefix={arXiv},
      primaryClass={physics.chem-ph},
      url={https://arxiv.org/abs/2609.22490},
}