We are delighted to announce the release of Py-ChemShell 2021 (v21.0), the third beta release of the Python-based version of ChemShell.

Py-ChemShell 2021 introduces biomolecular modelling functionality into Py-ChemShell, with a new guided workflow for protein setup, solvation and equilibration via an interface to NAMD, and automated import of CHARMM and AMBER forcefields for QM/MM calculations on biomolecular systems. Other new features include a periodic QM/MM embedding scheme for surface-adsorbate systems, and new interfaces to Molpro, Gaussian and MNDO.

As with the last release, Py-ChemShell 2021 is suitable for production calculations on materials systems and we would encourage materials modellers using the Tcl-based version of ChemShell to consider switching to Py-ChemShell for their production work if they haven’t already done so. Tcl-ChemShell will continue to be maintained, but not actively developed in future.

We would also like to encourage experienced ChemShell users to try the new biomolecular modelling functionality and send us their feedback. For production calculations on biomolecular systems we continue to recommend Tcl-ChemShell for the time being, until the next beta release scheduled for summer 2022.

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.