Pseduo-Canonical Orbitals

[Shai Ronen]

Hello,
How are these orbitals defined? My guess is that they are obtained by first
obtaining the natural
orbitald, then diagonalizing the fock operator separately in the occupied
and unoccupied orbital subspaces,
with some critical occupancy value to define 'occupied' and 'unoccupied'
orbital. Is this correct?
Also what is the meaning of the final occupancy of these orbitals? Since
they are not natural orbitals the reduced one electron density matrix is not
diagonal in this basis. Are the occupancy numbers the diagnoal elements of
this (non-diagonal) matrix?

Many thanks,
Shai Ronen

Shai Ronen                E-mail: sronen at post.tau.ac.il
School of Chemistry
Tel Aviv University      |   Fax: (972)-3-6405911
Tel Aviv 69978, Israel  |  Phone: (972)-3-6405910