If your journal accepts such simple citations as the URL of a website
only, this can be a proper citation:
Chemcraft - graphical software for visualization of quantum chemistry
computations. Version 1.8, build 648. https://www.chemcraftprog.com
If you need a more detailed citation, please email to our
email address and we will give you the proper citation.
Note that the surname of the
author of Chemcraft program presented at this website is a pseudonym, so
you should not use it in the citation.