Gaussian 03 Online Manual
Last update: 2 October 2006


This keyword selects the algorithm used for solving the CPHF equations [435,436,437,438,439,440,441,442,443,444].

Specify the integration grid for the CPHF portion of the calculation. The syntax is the same as for the Int=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 or Fine grid, the Coarse grid is used for the CPHF (a pruned (35,110)), and when UltraFine is used for the integrals, then SG1 is used for the CPHF. SG1 is the default grid for Polar=OptRot and Freq=Anharmonic.

Perform frequency-dependent CPHF, reading in the frequencies for the electromagnetic field perturbation. The default is a static frequency calculation. This option causes the desired frequency to be read from the input stream. The default units for this value are Hartrees. Other units may be specified by including a suffix, one of cm (cm-1) and nm (wave numbers). This option is relevant for Freq and Polar jobs.

Use equilibrium solvation. This is the default for static perturbations. NonEqSolv is the default for dynamic (non-zero frequency) perturbations.

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

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

Treat real and imaginary perturbations together. The opposite is NoXY, which does them separately. The default is to treat them separately if nuclear perturbations are also being done, but to treat them together if there are only electromagnetic perturbations.

Use the Z-Vector method [140,445,446] 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 3 x NAtoms CPHF for post-SCF gradients.

Solve CPHF in the atomic orbital basis [436,439,442,443]. This is the default.

Solve in the molecular orbital basis.

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.

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

Canonical CPHF, the default.

Use MOD orbital derivatives for SAC-CI gradients (which uses configuration selection).