Brillouin theorem
E675971
Brillouin theorem is a fundamental result in quantum chemistry and Hartree–Fock theory stating that single excitations from a Hartree–Fock ground state do not mix with the ground state and therefore do not lower its energy to first order.
Statements (43)
| Predicate | Object |
|---|---|
| instanceOf |
result in Hartree–Fock theory
ⓘ
result in quantum chemistry ⓘ theorem ⓘ |
| alsoKnownAs | Brillouin condition NERFINISHED ⓘ |
| appliesTo |
Hartree–Fock ground state
NERFINISHED
ⓘ
closed-shell Hartree–Fock solutions ⓘ single-determinant wavefunctions ⓘ |
| assumes |
Hartree–Fock orbitals are variationally optimized
ⓘ
the Hartree–Fock determinant is a stationary point of the energy NERFINISHED ⓘ |
| category |
Hartree–Fock method concept
ⓘ
electronic structure theory concept ⓘ quantum chemistry theorem ⓘ |
| concerns |
configuration interaction
ⓘ
first-order energy corrections ⓘ single excitations ⓘ stationary conditions of the Hartree–Fock energy ⓘ |
| doesNotHoldIf |
orbitals are not fully optimized
ⓘ
reference state is not a Hartree–Fock stationary point ⓘ |
| energyImplication | ground-state energy corrections start from double excitations in many-body expansions ⓘ |
| field |
quantum chemistry
ⓘ
quantum mechanics ⓘ theoretical chemistry ⓘ |
| holdsFor |
restricted Hartree–Fock
NERFINISHED
ⓘ
unrestricted Hartree–Fock ⓘ |
| implies |
configuration interaction singles (CIS) does not change the Hartree–Fock ground-state energy
ⓘ
correlation energy cannot be recovered from single excitations alone ⓘ first-order correction to the Hartree–Fock energy from single excitations is zero ⓘ matrix elements between the Hartree–Fock determinant and singly excited determinants vanish ⓘ the Hartree–Fock determinant is an eigenfunction of the Fock operator within the space of single excitations NERFINISHED ⓘ |
| mathematicalForm | ⟨Φ₀|H|Φᵢᵃ⟩ = 0 for all single excitations |Φᵢᵃ⟩ from the Hartree–Fock determinant |Φ₀⟩ ⓘ |
| namedAfter | Léon Brillouin NERFINISHED ⓘ |
| relatesTo |
Brillouin condition
NERFINISHED
ⓘ
Fock operator NERFINISHED ⓘ Slater determinants NERFINISHED ⓘ orbital rotations ⓘ |
| states |
single excitations do not lower the Hartree–Fock ground-state energy to first order
ⓘ
single excitations from a Hartree–Fock ground state do not mix with the ground state to first order ⓘ |
| usedIn |
Møller–Plesset perturbation theory
NERFINISHED
ⓘ
analysis of orbital optimization conditions ⓘ configuration interaction theory NERFINISHED ⓘ coupled-cluster theory ⓘ derivation of post-Hartree–Fock methods ⓘ |
| yearProposed | 1930s ⓘ |
Referenced by (1)
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