Wave-function and density functional theory studies of dihydrogen complexes

TL;DR

This study benchmarks wave-function and density functional theory methods on dihydrogen complexes, highlighting the strengths of second-order methods and the need for non-local exchange in DFT for better accuracy.

Contribution

It provides a reference set of dihydrogen bond distances and energies and evaluates the performance of various computational methods.

Findings

Second-order correlation methods perform well

Triple contributions improve accuracy

Density functional methods struggle to accurately predict both bond lengths and energies

Abstract

We performed a benchmark study on a series of dihydrogen bond complexes and constructed a set of reference bond distances and interaction energies. The test set was employed to assess the performance of several wave-function correlated and density functional theory methods. We found that second-order correlation methods describe relatively well the dihydrogen complexes. However, for high accuracy inclusion of triple contributions is important. On the other hand, none of the considered density functional methods can simultaneously yield accurate bond lengths and interaction energies. However, we found that improved results can be obtained by the inclusion of non-local exchange contributions.