Brueckner orbitals

[John Kerkines]

On Tue, 25 Sep 2001, H.-J. Werner wrote:

> This is to inform you that in the upcoming version 2001.1 the 
> first-order density matrices will be available for MP2 and QCISD
> and can be in dump records as usual. The same is true
> for the corresponding natural orbitals. I am sorry, but 
> this feature is not and will not be available in 2000.1.
> 
> Following your note, I will also modify the program to store
> the Brueckner orbitals in a dump record. However, I do not
> believe that it is a correct appraoch to use the Brueckner
> orbitals to produce a density matrix. The correct effective
> densities require to perform CPHF and CPCC calculations in order
> to compute the response of the orbitals and amplitudes. This
> is rather complicated stuff and unfortunately not so quick
> to implement for all methods (CCSD, MP3 and MP4 are under way).

Will the 2001.1 version support relativistic corrections (perturbational)
for other methods apart from SCF, CASSCF, CISD and MRCI?

John Kerkines