What type of QM/MM calculations are available?

The QM/MM interface only supports a subset of the functionality of CPMD. Please note, that although there are some tests and warnings included into the source code, not every job that runs without a warning will be automatically correct. So far, the interface code requires the use of norm-conserving pseudopotentials. Tested and supported job types are: MOLECULAR DYNAMICS (CLASSICAL, CP and BO), OPTIMIZE WAVEFUNCTION, KOHN-SHAM ENERGIES, and ELECTRONIC SPECTRA. Supported are closed shell systems as well as LSD and LOW SPIN EXCITATION calculations.

OPTIMIZE GEOMETRY is experimental and currently supports optimization of the QM atom positions only. Use of the linear scaling geometry optimizer (LBFGS) is highly recommended and the currently also the default.

PROPERTIES calculations with QM/MM are experimental. Most properties (WF projection, population analysis, localization) that only need the plain QM wavefunction work.

LINEAR RESPONSE calculations are currently at an twofold experimental status. Both, the isolated system setup (SYMMETRY 0) and the QM/MM coupling of the response calculations itself are not yet fully tested.

Options that are known to be incompatible with QMMM are VIBRATIONAL ANALYSIS, PATH INTEGRAL, and all calculations that require a wavefunction optimization via a diagonalization method at some point.