Molecular Systems

GMTKN55

Summary

Performance in evaluating gas-phase chemical accuracy for main group thermochemistry, kinetics and noncovalent interactions, through 55 test sets, totalling 1,505 relative energies, categorised into five chemical domains.

Metrics

  1. Small systems

Weighted mean absolute deviation (MAD) of basic properties, such as atomic energies, ionisation potentials, and electron affinities, of small systems.

For each system, the relative energy is calculated and compared to the reference energy. The MAD is calculated for each of the subsets within this category, including only neutral singlet systems. A weighted sum is calculated by multiplying each subset error by a weight and the number of systems in the subset. This is divided by the total number of systems within these subsets.

  1. Large systems

Weighted mean absolute deviation (MAD) of reaction energies of large systems and isomerisation energies.

Same as (1), for the appropriately categorised subsets.

  1. Barrier heights

Weighted mean absolute deviation (MAD) of reaction barrier heights for transition state energetics for fundamental organic reactions.

Same as (1), for the appropriately categorised subsets.

  1. Intramolecular NCIs

Weighted mean absolute deviation (MAD) of intramolecular noncovalent interactions for conformational energetics and hydrogen bonding.

Same as (1), for the appropriately categorised subsets.

  1. Intermolecular NCIs

Weighted mean absolute deviation (MAD) of intermolecular noncovalent interactions for dimers, clusters, and host-guest complexes.

  1. All (WTMAD)

Weighted mean absolute deviation (MAD) of all subsets.

Same as (1), for all subsets.

Computational cost

Low: tests are likely to take minutes to run on CPU.

Data availability

Input structures:

  • L. Goerigk, A. Hansen, C. Bauer, S. Ehrlich, A. Najibi, and S. Grimme, A look at the density functional theory zoo with the advanced gmtkn55 database for general main group thermochemistry, kinetics and noncovalent interactions, Physical Chemistry Chemical Physics 19, 32184 (2017).

Reference data:

  • Same as input data

  • PBE-D3(BJ)

Wiggle150

Summary

Performance in predicting relative energies between 150 strained conformers of adenosine, benzylpenicillin, and efavirenz molecules (50 each) and their geometry optimised structures.

Metrics

  1. Relative energy MAE

Accuracy of relative energy predictions.

For each molecule, 50 relative energies are calculated by comparing the predicted energy of the DLPNO-CCSD(T)/CBS geometry optimised structure to the energies of its 50 strained conformers. The mean absolute error is reported over all 150 conformers.

Computational cost

Low: tests are likely to take less than a minute to run on CPU.

Data availability

Input structures:

  • Brew, R. R. et al. Wiggle150: Benchmarking Density Functionals and Neural Network Potentials on Highly Strained Conformers. J. Chem. Theory Comput. 21, 3922-3929 (2025).

Reference data:

  • Same as input data

  • DLPNO-CCSD(T)/CBS