Extended Hückel method
E381908
The Extended Hückel method is a semi-empirical quantum chemistry approach developed by Roald Hoffmann to approximate molecular electronic structure and bonding using simplified orbital interactions.
All labels observed (2)
| Label | Occurrences |
|---|---|
| Extended Hückel method canonical | 1 |
| extended Hückel Hamiltonian | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T3702713 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Extended Hückel method Context triple: [Roald Hoffmann, hasWork, Extended Hückel method]
-
A.
Hartree–Fock method
The Hartree–Fock method is an approximate quantum mechanical approach for determining the electronic structure of atoms, molecules, and solids by modeling electrons as occupying self-consistent single-particle orbitals.
-
B.
MOPAC
MOPAC is the strategic oversight body responsible for holding the Metropolitan Police Service in London to account and setting policing priorities on behalf of the Mayor.
-
C.
Herzberg–Teller approximation
The Herzberg–Teller approximation is a refinement in molecular spectroscopy that accounts for vibronic coupling by allowing electronic transition dipole moments to depend on nuclear coordinates, explaining intensity in otherwise forbidden transitions.
-
D.
Born–Oppenheimer approximation
The Born–Oppenheimer approximation is a fundamental method in molecular quantum mechanics that simplifies calculations by treating nuclear motion as much slower than electronic motion, allowing their behaviors to be separated.
-
E.
Longuet-Higgins theorem in molecular symmetry
The Longuet-Higgins theorem in molecular symmetry is a fundamental result in theoretical chemistry that relates molecular symmetry properties to electronic state degeneracies and the occurrence of phenomena such as the Jahn–Teller effect.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Extended Hückel method Target entity description: The Extended Hückel method is a semi-empirical quantum chemistry approach developed by Roald Hoffmann to approximate molecular electronic structure and bonding using simplified orbital interactions.
-
A.
Hartree–Fock method
The Hartree–Fock method is an approximate quantum mechanical approach for determining the electronic structure of atoms, molecules, and solids by modeling electrons as occupying self-consistent single-particle orbitals.
-
B.
MOPAC
MOPAC is the strategic oversight body responsible for holding the Metropolitan Police Service in London to account and setting policing priorities on behalf of the Mayor.
-
C.
Herzberg–Teller approximation
The Herzberg–Teller approximation is a refinement in molecular spectroscopy that accounts for vibronic coupling by allowing electronic transition dipole moments to depend on nuclear coordinates, explaining intensity in otherwise forbidden transitions.
-
D.
Born–Oppenheimer approximation
The Born–Oppenheimer approximation is a fundamental method in molecular quantum mechanics that simplifies calculations by treating nuclear motion as much slower than electronic motion, allowing their behaviors to be separated.
-
E.
Longuet-Higgins theorem in molecular symmetry
The Longuet-Higgins theorem in molecular symmetry is a fundamental result in theoretical chemistry that relates molecular symmetry properties to electronic state degeneracies and the occurrence of phenomena such as the Jahn–Teller effect.
- F. None of above. chosen
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
computational chemistry method
ⓘ
molecular orbital method ⓘ semi-empirical quantum chemistry method ⓘ |
| appliedTo |
cluster compounds
ⓘ
inorganic complexes ⓘ organic molecules ⓘ solid-state band structure approximations ⓘ transition metal complexes ⓘ |
| approximates |
chemical bonding
ⓘ
molecular electronic structure ⓘ |
| associatedWith |
Nobel Prize in Chemistry 1981 for Roald Hoffmann
ⓘ
surface form:
Nobel Prize in Chemistry 1981 (for Roald Hoffmann’s theoretical work on chemical bonding)
|
| assumes | zero differential overlap approximation for two-electron integrals ⓘ |
| basedOn |
Hückel molecular orbital theory
ⓘ
surface form:
Hückel molecular orbital method
|
| calculates |
approximate charge distribution
ⓘ
bond orders ⓘ molecular orbital coefficients ⓘ molecular orbital energies ⓘ |
| characteristic |
computationally inexpensive
ⓘ
qualitative accuracy ⓘ suitable for large systems ⓘ |
| developer | Roald Hoffmann ⓘ |
| field |
quantum chemistry
ⓘ
theoretical chemistry ⓘ |
| influenced | development of modern semi-empirical methods ⓘ |
| limitation |
limited treatment of electron correlation
ⓘ
poor quantitative prediction of energies ⓘ sensitivity to parameter choice ⓘ |
| neglects |
electron correlation
ⓘ
electron–electron repulsion integrals ⓘ |
| notableUser | Roald Hoffmann ⓘ |
| relatedTo |
CNDO method
ⓘ
Hückel molecular orbital theory ⓘ
surface form:
Hückel theory
INDO method ⓘ MNDO method ⓘ semi-empirical MO methods ⓘ tight-binding method ⓘ |
| usedFor |
interpretation of molecular bonding patterns
ⓘ
qualitative molecular design ⓘ rationalization of reactivity trends ⓘ |
| uses |
Slater-type orbital basis sets
ⓘ
surface form:
Slater-type orbitals
atomic valence orbitals ⓘ empirical parameters ⓘ Extended Hückel method self-linksurface differs ⓘ
surface form:
extended Hückel Hamiltonian
overlap integrals ⓘ valence orbital ionization potentials ⓘ |
| usesFormula |
Hii equals valence orbital ionization potential
ⓘ
Hij proportional to overlap integral Sij ⓘ |
| yearProposed | 1963 ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Extended Hückel method Description of subject: The Extended Hückel method is a semi-empirical quantum chemistry approach developed by Roald Hoffmann to approximate molecular electronic structure and bonding using simplified orbital interactions.
Referenced by (2)
Full triples — surface form annotated when it differs from this entity's canonical label.
this entity surface form:
extended Hückel Hamiltonian