keywords indicate that additional basis functions are to be added to the basis
set or density fitting basis set specified in the route section for the calculation
(respectively). These basis functions appear in a separate section in the input
stream, using any of the valid formats (which are described in detail in the discussion
of the Gen keyword).
ExtraBasis is most useful for supplying basis functions for elements
undefined in a standard basis set. It cannot be used to replace
a definition within a built-in basis set, and attempting to do so will
result in an error. All basis functions specified with this keyword are
added to the ones in the basis set specified in the route section.
For these reasons, Gen is often easier
to use than ExtraBasis; consult the description for that keyword
before deciding to use this one.
ExtraDensityBasis is ignored if no density fitting basis is specified
in the route.
The following job uses the 6-31G(d,p) basis set along with an additional
diffuse function on all of the carbon atoms:
# HF/6-31G(d,p) ExtraBasis ...
SP 1 1.00
0.4380000000D-01 0.1000000000D+01 0.1000000000D+01
The following job supplies additional functions for both the basis set
and for density fitting:
#p rblyp/6-31g*/dga1 extrabasis extradensitybasis 6d
HCl using the internally stored 6-31g* AO basis & DGA1 fitting set,
adding f functions to the AO basis, and f & g fitting functions
! here are some extra AO polarization functions
F 1 1.00 0.000000000000
p 1 1.00 0.000000000000
! here are some extra fitting functions.