Note

This website is presently under development. The primary website for MOPAC is still http://openmopac.net until the majority of its contents have been migrated here.

REORTH

During a MOZYMErun, the steady accumulation of small errors (for example, roundoff, and more important, the elimination of atoms from LMOs) will result in the LMOs becoming non-orthogonal. These errors can be eliminated almost completely by re-orthogonalizing the LMOs. If REORTH is present, then the LMOs will be re-orthogonalized at the end of every 10th SCF calculation, starting with the first SCF.

In practice, a better strategy is to allow the job to run for ~500 cycles or 1-2 CPU days, then shut it down and restart it using `RESTART <restart.html>`__, but without using keyword `OLDENS <oldens.html>`__.  That will cause the LMO’s to be recalculated, and job to resume starting with the geometry at the end of the previous run.