These method keywords request an electron propagator theory calculation of correlated electron affinities and ionization potentials [Cederbaum75, Cederbaum77, Ohrn81, vonNiessen84, Ortiz88, Ortiz88a, Ortiz89, Zakrzewski93, Zakrzewski94a, Zakrzewski95, Ortiz96, Zakrzewski96, Ortiz97, Ferreira01, Linderberg04].
EPT 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.
This keyword was formerly named OVGF.
OVGF
Use the Outer Valence Green’s Function propagator. This is the default.
P3
Use the P3 propagator.
OVGF+P3
Use both propagator methods.
FC
All frozen core options are available with this keyword. See the discussion of the FC options for full information.
ReadOrbitals
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).
ForceSort
Forces sorting of intermediate quantities to be done even when it is not necessary. This option appears in some G09 test jobs, but it is not useful for production calculations.
Single point energy calculations only.
For EPT 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).
Last updated on: 10 May 2009