23.6 CPHF for gradients, expectation values and polarizabilities
The accuracy and other parameters of the CPHF calculations necessary to compute gradients and response properties
can be modified using the CPHF directive:
- CPHF convergence threshold (default 1.d-6). THRESH and ACCU are aliases for this.
- initial CPHF convergence threshold in geometry optimizations. Once the geometry is converged to
a certain accuarcy (depending on OPTCONV), the threshold is stepwise reduced to THRMIN.
The default is THRMAX=min(1.d-6,THRMIN*100); Values larger than 1.d-6 are ignored.
- Maxmimum number of iterations (default 50).
- Level shift for CPHF (default 0.1).
- First macroiteration in which DIIS is used (default 1)
- First microiteration in which DIIS is used (default 1; in microiterations the core contribution is frozen).
- Record on which the CPHF solution can be saved for later restarts. The solution is saved
automatically in geometry optimizations and frequency calculations.
- Record from which initial guess is read. A starting guess is read automatically in geometry optimizations
and frequency calculations.
In density-fitting MP2, only THRMIN is active, the rest of the options are handled automatically.