Interface to the Orca package (https://orcaforum.cec.mpg.de/, free license for academic use). The interface was developed for version 2.9 and tested to work with 3.0.2. There are some changes in the input for Orca 4.0 and the interface was not tested thoroughly with this version.

Orca provides access to wide range of DFT and ab initio methods, both DFT and correled calculations can used the Resolution of identity approximation.

HF-3c and PBEh-3C

Orca implements small-basis HF/DFT calculations with the 3c corrections. The 3c stands for three corrrections for 1) dispersion, 2) basis set superposition error and 3) additional basis set incompleteness effects. Two versions are available, HF-3c based on Hartree-Fock calculation in minimal basis set[1] and PBEh-3c based on DFT in a double-zeta basis.[2] Using these methods activates the complete setup including the basis set for which the corrections were developed, no further setup is needed – see the example below.

Non-standard behavior

References

  1. R. Sure, S. Grimme, J. Comput. Chem., 2013, 34, 1672-1685
  2. S. Grimme, J. G. Brandenburg, C. Bannwarth, A. Hansen, The Journal of Chemical Physics, 2015, 143, 054107