Subject: DIIS in CPHF convergence.

From: Ed Brothers <[email-masked]>
Date: Wed, 11 Dec 2002 12:09:10 -0500

I am currently implementing the CPHF in oreder to calculate an
analytical hessian.  I have previously used DIIS for SCF convergence
acceleration.
    In DIIS-SCF, the error is defined as FDS-SDF, where F is the fock
matrix, D is the density matrix, and S is the overlap matrix.  How do I
set up the error values in CPHF to accelerate convergence?
    Thanks for any help you can give me.

        Ed Brothers.
        Merz Group
        Penn State