We are delighted to announce the release of Py-ChemShell 2020 (v20.0), the second beta release of the Python-based version of ChemShell.

Py-ChemShell 2020 includes improved cluster cutting functionality, an interface to FHI-aims, improved wavefunction guesses for NWChem and a new set of tutorials covering first steps with the software up to full QM/MM calculations, as well as a huge number of improvements behind the scenes.

We now recommend that materials modellers still using the Tcl-based version of ChemShell should consider switching to Py-ChemShell for their production work. Tcl-ChemShell will continue to be maintained, but not actively developed in future. Biomolecular modellers should continue to use Tcl-ChemShell for the time being, but we expect to include biomolecular workflows in our next release due later this year.

Py-ChemShell can be downloaded free of charge under the open source GNU LGPL v3 licence from this site. If you have any questions about the code, please get in touch via the user forums.