11.7.5 Read an External Potential From a File

Users can introduce an external potential affecting the active molecule in a DFT calculation, representing an embedding environment. Any functional can be used. To invoke the reading of an external potential, users must set the key-word PROJ_CAP = -10 in the $rem section, and the file named external_potential.grid must be present at the same directory. The external potential must be expressed at the same exact grid points. The potential file includes only the potential values in atomic coordinates. As a preparation step the grid points can be printed using libqints by setting the flag use_libqints = true. A related published work ²¹⁵ Chakravarty. C. et al.
J. Phys. Chem. Lett.
(2022), 13, pp. 4849. Link can also be read in order to see its usage in different DFT functional.