CPHF Keyword
Last Update: 6/26/2001

This keyword selects the algorithm used for solving the CPHF equations [207,208,209,210,211,212,213,214,215,216].

Grid=grid
Specify the integration grid for the CPHF portion of the calculation. The syntax is the same as for the Integral=Grid option. The argument to this option may be a grid keyword (Fine, UltraFine, and so on) or a specific grid. See the discussion of Integral=Grid for full details on grid specification.

The default grid used depends on the one used for integral evaluation. If any specific grid is specified to the Integral keyword, then that grid is also used for the CPHF. Otherwise, when the latter uses the SG1 orFine grid, the Coarse grid is used for the CPHF (a pruned (35,11));, and when UltraFine is used for the integrals, then SG1 is used for the CPHF.

Simultaneous
Use one expansion space for all variables. This is faster than using separate spaces, but is slightly less accurate. This is the default.

Separate Use a separate expansion space for each variable in the CPHF (the opposite of Simultaneous).

ZVector
Use the Z-Vector method [92,217-218] for post-SCF gradients. Allowed and the default if Hartree-Fock 2nd derivatives are not also requested. The NoZVector keyword says to use the full 3xN_Atoms CPHF for post-SCF gradients.

AO
Solve CPHF in the atomic orbital basis [208,211,214-215]. This is the default for Hartree-Fock second derivatives (which is also the only calculation type for which it is valid).

MO
Solve in the molecular orbital basis. It is the default and only legal value for PSCF gradients.

MaxInv=N
Specifies the largest reduced space for in-core inversion during simultaneous solution (up to dimension N). Larger reduced problems are solved by a second level of DIIS. The default is as large a space as memory permits.

Conver=N
Set the CPHF convergence criterion to 10^-N. The default is N=9 for CPHF=Separate and N=10 for CPHF=Simultaneous (the default).

SCF

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