Condon approximation
E147782
The Condon approximation is a simplifying assumption in molecular spectroscopy that treats electronic transition dipole moments as independent of nuclear coordinates, enabling easier calculation of vibronic transition intensities.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Condon approximation canonical | 2 |
How this entity was disambiguated
This entity first appeared as the object of triple T1295690 — 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: Condon approximation Context triple: [Herzberg–Teller approximation, contrastsWith, Condon approximation]
-
A.
Migdal approximation
The Migdal approximation is a theoretical simplification in many-body physics that neglects vertex corrections in electron-phonon interactions, justified when phonon energies are much smaller than electronic energies.
-
B.
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.
-
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.
Rayleigh–Schrödinger perturbation theory
Rayleigh–Schrödinger perturbation theory is a fundamental method in quantum mechanics for approximating the energies and states of a system by treating interactions as small corrections to an exactly solvable problem.
-
E.
Born–Huang expansion
The Born–Huang expansion is a quantum mechanical method that systematically improves upon the Born–Oppenheimer approximation by including couplings between electronic and nuclear motions in molecular systems.
- 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: Condon approximation Target entity description: The Condon approximation is a simplifying assumption in molecular spectroscopy that treats electronic transition dipole moments as independent of nuclear coordinates, enabling easier calculation of vibronic transition intensities.
-
A.
Migdal approximation
The Migdal approximation is a theoretical simplification in many-body physics that neglects vertex corrections in electron-phonon interactions, justified when phonon energies are much smaller than electronic energies.
-
B.
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.
-
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.
Rayleigh–Schrödinger perturbation theory
Rayleigh–Schrödinger perturbation theory is a fundamental method in quantum mechanics for approximating the energies and states of a system by treating interactions as small corrections to an exactly solvable problem.
-
E.
Born–Huang expansion
The Born–Huang expansion is a quantum mechanical method that systematically improves upon the Born–Oppenheimer approximation by including couplings between electronic and nuclear motions in molecular systems.
- F. None of above. chosen
Statements (46)
| Predicate | Object |
|---|---|
| instanceOf |
approximation in molecular spectroscopy
ⓘ
theoretical model in quantum chemistry ⓘ |
| appliesTo |
electronic transitions in molecules
ⓘ
vibronic transitions ⓘ |
| assumes |
electronic transition dipole moment is independent of nuclear coordinates
ⓘ
transition dipole moment varies slowly with nuclear geometry ⓘ |
| basedOn | Born–Oppenheimer approximation ⓘ |
| category |
quantum mechanical approximation
ⓘ
spectroscopic approximation ⓘ |
| concerns |
electronic transition moment operator
ⓘ
nuclear vibrational wavefunctions ⓘ |
| contrastedWith |
Herzberg–Teller approximation
ⓘ
surface form:
Herzberg–Teller expansion of transition moment
non-Condon effects ⓘ |
| field |
molecular physics
ⓘ
molecular spectroscopy ⓘ quantum chemistry ⓘ |
| goal |
provide tractable expressions for spectral intensities
ⓘ
simplify calculation of transition probabilities ⓘ |
| hasConsequence |
electronic transition moment treated as a constant prefactor in intensity expressions
ⓘ
intensity distribution determined mainly by overlap of vibrational wavefunctions ⓘ |
| historicalContext | introduced in early quantum theory of molecular spectra ⓘ |
| implies |
separation of electronic and nuclear contributions to transition intensity
ⓘ
transition intensity proportional to Franck–Condon factor ⓘ |
| involves |
Born–Oppenheimer approximation
ⓘ
surface form:
Born–Oppenheimer separation of variables
factorization of electronic and vibrational integrals ⓘ |
| limitations |
fails when vibronic coupling is strong
ⓘ
inaccurate for symmetry-forbidden or weakly allowed transitions ⓘ inadequate when electronic and nuclear motions are strongly mixed ⓘ |
| mathematicalForm | transition dipole moment treated as constant with respect to nuclear coordinates ⓘ |
| namedAfter |
Edward Condon
ⓘ
surface form:
Edward U. Condon
|
| relatedTo |
Franck–Condon principle
ⓘ
Herzberg–Teller approximation ⓘ transition dipole moment ⓘ vibronic coupling ⓘ |
| typicalApplication |
diatomic molecular electronic spectra
ⓘ
polyatomic molecular UV–vis spectra ⓘ |
| usedFor |
analysis of absorption spectra
ⓘ
analysis of emission spectra ⓘ analysis of fluorescence spectra ⓘ analysis of phosphorescence spectra ⓘ calculation of vibronic transition intensities ⓘ simplifying evaluation of Franck–Condon factors ⓘ |
| usedIn |
computational spectroscopy
ⓘ
interpretation of band shapes in molecular spectra ⓘ theoretical modeling of electronic spectra ⓘ |
| validWhen | transition dipole moment does not change significantly over nuclear configuration space of interest ⓘ |
How these facts were elicited
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Instruction
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Input
Subject: Condon approximation Description of subject: The Condon approximation is a simplifying assumption in molecular spectroscopy that treats electronic transition dipole moments as independent of nuclear coordinates, enabling easier calculation of vibronic transition intensities.
Referenced by (2)
Full triples — surface form annotated when it differs from this entity's canonical label.