Abstract
We present a new benchmark set consisting of 16 large non-covalently bound systems
(LNCI16) ranging from 380 up to 1988 atoms and featuring diverse interaction motives.
Gas-phase interaction energies are calculated with various composite DFT, semi-empirical
quantum mechanical (SQM), and force field (FF) methods and are evaluated using accurate
DFT reference values. Of the employed QM methods, PBEh-3c proves to be the most robust
for large systems with a relative mean absolute deviation (relMAD) of 8.5% with respect
to the reference interaction energies. r2SCAN-3c yields an even smaller relMAD, at least for the subset of complexes for which
the calculation could be converged, but is less robust for systems with smaller HOMO–LUMO
gaps. The inclusion of Fock-exchange is therefore important for the description of
very large non-covalent interaction (NCI) complexes in the gas phase. GFN2-xTB was
found to be the best performer of the SQM methods with an excellent result of only
11.1% deviation. From the assessed force fields, GFN-FF and GAFF achieve the best
accuracy. Considering their low computational costs, both can be recommended for routine
calculations of very large NCI complexes, with GFN-FF being clearly superior in terms
of general applicability. Hence, GFN-FF may be routinely applied in supramolecular
synthesis planning.
1 Introduction
2 The LNCI16 Benchmark Set
3 Computational Details
4 Generation of Reference Values
5 Results and Discussion
6 Conclusions
Key words
non-covalent interaction energies - benchmarking - dispersion - composite methods
- semi-empirical methods - force fields
