CorrelationEnergy computes the correlation energy, the difference between the exact energy and Hartree-Fock energy.

The procedure returns the correlation energy as a float.

The default method is 'HartreeFock' method whose correlation energy is 0.

The result depends upon the chosen molecule, method, and basis set among other options such as charge, spin, and symmetry.

Because the methods employ Maple cache tables, the procedure only computes the correlation energy if it has not been previously computed by calling the method directly or indirectly through another property.

$\mathrm{with}\left(\mathrm{QuantumChemistry}\right)\:$

$\mathrm{molecule} ≔ \left[\left[''H''\,0\,0\,0\right]\,\left[''F''\,0\,0\,0.95\right]\right]\;$

$\mathrm{molecule}≔\left[\left[''H''\,0\,0\,0\right]\,\left[''F''\,0\,0\,0.95000000\right]\right]$

$\mathrm{output\_hf} ≔ \mathrm{CorrelationEnergy}\left(\mathrm{molecule}\right)\;$

$\mathrm{output\_hf}≔0.$

$\mathrm{output\_hf} ≔ \mathrm{CorrelationEnergy}\left(\mathrm{molecule}\, \mathrm{method}\=\mathrm{MP2}\right)\;$

$\mathrm{output\_hf}≔\mathrm{-0.01882706}$