Page 195 - Strategies and Applications in Quantum Chemistry From Molecular Astrophysics to Molecular Engineer
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178 Y. G. SMEYERS ET AL.
and
In these equations, S is the overlap between the two determinants built up with
corresponding orbitals (12)(multiplied by a phase factor according the multiplicity
required):
and
is defined as a cross operator analogous to the Fock operator (8):
A similar operator can be written for the case in which a b i orbital is replaced by a
virtual one,
Introducing now expressions (13) and (14) in (4) , the following equation is obtained:
