STATIC ELECTRON CORRELATION ENERGY



1999 July 30
                   DYNAMIC AND STATIC ELEC TRON CORRELATION ENERGY
  Correlation energy is sometimes divided into dynamic and static. Dynamic
 CE is the deviation from the exact energy caused by not allowing electrons to
 keep apart properly. It can be calculated ("recovered") by
 Moller-Plesset
 (e.g. MP2, MP4) or configuration interaction calculations. Static CE is the
 deviation from the exact energy caused by trying to represent a wavefunction
 by just one determinant when at least two are really needed, as with a singlet
 diradical.
 QUESTION: Is it true that a common and correct way to handle static CE is
 with multifererence configuration interaction (MRCI)?
   Thanks
     E. Lewars
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