34.2.12 Number of point used in hessian update (UPDATE)

UPDATE,type=nstep

This option chooses the update type to be used and limits the number of points used for the hessian update to nstep. In minimizations type may be

BFGS

Use BFGS update of hessian (default).

IBFGS

Use BFGS update of the inverse hessian.

CGRD

Use Conjugate Gradient update (see also CUT,TRUST).

NONE

Don't do any update.

The default number of steps used in hessian update procedures is 5. If there are symmetry constraint in the coordinates of the optimization, the default number may be lower than five. On input, nstep steps will be used for update, ignoring any symmetry constraints.

In transition state optimizations type may be

PMS

Combined Powell/Murtagh-Sargent update of hessian (default).

POWELL

Use Powell's update of the hessian.

MS

Use update procedure of Murtagh and Sargent.

NONE

Don't do any update.