Fock Matrix in Original Basis

Following SCF calculations I am trying to output the Fock matrix in the original (AO) basis - without success. I have tried using the method Fa_subset( , ) but this is not recognised by the computation, despite many different attempts with different syntax. Any help appreciated. Thanks.

Something like this?

e,wfn =energy('hf',return_wfn=True)
F_ao = wfn.Fa_subset("AO").to_array() # psi4 object to numpy array; see core.Vector class

Many thanks for your reply - still having problems. See input and error message below (testing optimizer).

memory 600 mb

molecule ch4 {
C 0 0 0
H 1 0 0.1
H -0.5 0.1 0.5
H -0.5 0.5 -0.6
H -0.6 -0.5 -0.5
}

set basis cc-pVDZ
optimize(“scf”)
E,wfn=energy(“scf”,return_wfn=True)
F_ao=wfn.Fa_subset(“AO”)

Optimizer: Optimization complete!
Traceback (most recent call last):
File “/home/donald/psi4conda/bin/psi4”, line 269, in
exec(content)
File “”, line 34, in

AttributeError: ‘psi4.core.RHF’ object has no attribute ‘Fa_subset’

What am I missing? Thanks in anticipation.

What version of Psi4 do you have?

Output files show Psi4 1.2.1

You may need Psi4 1.3+ to use this feature.