From: Marcin Modrzejewski
<modrzej,+,tiger.chem.uw.edu.pl>
Subject: CCL:G: incremental and nonincremental Fock matrix
Date: Thu, 8 Mar 2012 14:19:54 +0100
Dear Reza,
Incremental Fock matrix build means that its Coulomb and exchange
components are generated from difference between the current density matrix and
the density matrix from previous iteration. This matrices are then added to the
Fock matrix from previous iteration. It can be done because Coulomb and exchange
matrices are linear with respect to density matrix elements. Such an algorithm
can significantly speed up the direct Fock matrix build thanks to extensive
integral screening [Schwegler, E. et al. J.Chem.Phys. 106, 9708]. However, if large number
of diffuse functions is present, this option might worsen the SCF
convergence.
Sent to CCL by: "Reza ÂShojaei" [shojaei81%%gmail.com]
Dear all,
Do you have any idea about the exact meanning of incremental Fock Âmatrix
which is default setting for direct SCF.
What's the non incremental fock matrix?
here I put the Gaussian's manual which I don't understand:
"IncFock:
Forces use of incremental Fock matrix formation. This is the default for direct
SCF. NoIncFock prevents the use of incremental Fock matrix formation, and it is
the default for conventional SCF. "