Gaussian 03 Online Manual
Last update: 2 October 2006


These method keywords request an Outer Valence Green's Function (propagator) calculation of correlated electron affinities and ionization potentials [243,244,245,246,247,248,249,549].

OVGF calculations default to storage of <ia||bc> integrals, but can be run Tran=Full to save CPU time at the expense of disk usage, or with Tran=IJAB to save on disk space at the expense of CPU time. In the latter case, electron affinities are not computed.

By default, only ionization potentials which are < 20 eV are computed.

Use ReadOrbitals option to specify the starting and ending orbitals to refine as input. By default, all orbitals are used.

The frozen-core options for defining inner-shells to be excluded from the correlation calculation are valid with this keyword. See the discussion here for details.

Specify starting and ending orbitals to refine, in a separate, blank-terminated input section. For unrestricted calculations, separate ranges are specified for alpha and beta orbitals (on the same input line).

Single point energy calculations only.

For OVGF calculations, the results for each orbital appear as follows:

Summary of results for alpha spin-orbital   6    P3: 
Koopmans theorem:             -0.72022D+00 au  -19.598 eV 
Converged second order pole: -0.61437D+00 au  -16.718 eV  0.840 (PS) 
Converged 3rd order P3 pole: -0.63722D+00 au  -17.340 eV  0.854 (PS) 

The second output line gives the estimate of ionization potential/electron affinity for the specified orbital (which property is given depends on whether the orbital is occupied or not, respectively) . The pole strength is a measure of how easy it is to make this excitation, with 1.0 as the maximum value. Note that orbitals are listed in the output in order of symmetry (and not necessarily in numerical order).