Brueckner orbitals

Andreas Hesselmann andreas at
Tue Sep 25 15:42:45 BST 2001

Hello again,

the occupations for building the density matrices
can simply be looked up from previous SCF
calculations. Furthermore, if your molecule has
no symmetry, then you can of course enter just
the number of occupied orbitals in the 'dens' card,
e.g. in case of the water molecule you write
in your molpro input.

One added note:
using Brueckner orbitals as a density source
can be seen as simplest scheme of a coupled
cluster expectation value expansion and of
course does not account for the total correlation
effect of the underlying cc-method. 


 Andreas Hesselmann                                        
 Institut fuer Theoretische Chemie                        
 Heinrich-Heine Universitaet                              
 Universitaetsstrasse 1 / 40225 Duesseldorf          
 Phone:  +49-211 / 8111439                              
 Fax:      +49-211 / 8113466                              
 E-Mail:  andreas at  

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