40.2.9 Hessian update (UPDATE)

UPDATE,[TYPE=]type,MAX=maxupd

This directive chooses the update type and limits the number of points used for the hessian update to maxupd. 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.

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.

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.