Conservation of the correlation

To summarize the discussion in this section, it is fair to state that the Hartree-Fock approximation is adequate in many cases. If a rough conservation of the correlation energy may be expected, the Hartree-Fock energy predictions are mostly within 20 kO/mole or even better. In the past the importance of correlation effects was sometimes overestimated and the discrepancy with experiment found in a particular problem was later attributed to the limited basis set. Very instructive discussions on this problem were reported for the heats of... 

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