compute the correlation energy
CorrelationEnergy(molecule, method, options)
list of lists; each list has 4 elements, the string of an atom's symbol and atom's x, y, and z coordinates
(optional) method = name/procedure where name is one of 'HartreeFock' (default), 'DensityFunctional','ActiveSpaceCI', 'ActiveSpaceSCF', 'CoupledCluster', 'FullCI', 'MP2', 'Variational2RDM', 'ContractedSchrodinger'
(optional) equation(s) of the form option = value where option is any valid option of the chosen method
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.
Computation of the correlation energy of the hydrogen fluoride HF molecule with the MP2 method
molecule ≔ H,0,0,0,F,0,0,0.95;
output_hf ≔ CorrelationEnergymolecule;
output_hf ≔ CorrelationEnergymolecule, method=MP2;
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