Known MM-MD related CP2K issues and limitations

[BvB93]

Known CP2K related issues and limiations:

• CP2K 4.1 has issues reading atomic charges, raising complaints about a supposedly overcomplete set of keywords. This issue is absent in both CP2K 3.0 and 6.1

  • Error: Only one between <CHARGE_OCCUP,CHARGE_BETA,CHARGE_EXTENDED> can be defined!
  • Note: The error persists even if only a single (or none at all) of the mentioned keywords is present in the input file.

• CP2K cannot parse atom types with more than 4 characters. This includes many of the atom types defined by the CHARMM General Force Field for organic molecules (CGenFF) parameter set.

  • This character limitation was observed in the following issue: Topology error QMMM or MM.

• Issues have been encountered when reading parameter files (.prm) where the IMPROPERS block is not located at the end of the file.

  • Note: In the inverstigated CGenFF parameter set (Additive Force Field Files, July 2018 update) the IMPROPERS block is not located at the end of the file.