21.1.1 Options to control HF convergence

ACCU[RACY]=accu

Convergence threshold for the density matrix (square sum of the density matrix element changes). Tf accu$> 1$, a threshold of $10^-{accu}$) is used. The default depends on the global ENERGY threshold.

ENERGY=thrden

The convergence threshold for the energy. The default depends on the global ENERGY threshold.

START=record

Record holding start orbitals.

SAVE|ORBITAL=record

Dump record for orbitals.

MAXIT=maxit

Maximum number of iterations (default 60)

SHIFTA|SHIFTC=shifta

Level shift for closed-shell orbitals in RHF (default $-0.3$) and $\alpha$-spin orbitals in UHF (default 0).

SHIFTB|SHIFTO=shiftb

Level shift for open-shell orbitals in RHF and $\beta$-spin orbitals in UHF (default 0)

NITORD=nitord

In open-shell calculations, the orbitals are reordered after each iteration to obtain maximum overlap with the orbitals from the previous iteration. This takes only effect after nitord iterations. The default is nitord$=$maxit$/4$ if no start card is present and nitord$=1$ if a START card is found.

NITOCC=nitocc

Starting with iteration nitocc the occupation pattern is kept fixed. The default depends on the quality of the starting guess.

NITCL=nitcl

If the iteration count is smaller than nitcl, only the closed-shell part of the Fock matrix is used (default nitcl$=0$).

NITORT=nitort

The orbitals are reorthonormalized after every nitort iterations. The default is nitort$=10$.

POTFAC=potfac

Scale factor for potential energy in first iteration (default 1.0).