Longuet-Higgins theorem in molecular symmetry

E88919

result in theoretical chemistry theorem

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.

Statements (42)

Predicate	Object
instanceOf	result in theoretical chemistry → theorem →
addresses	conditions under which electronic degeneracy leads to instability → symmetry constraints on electronic energy levels →
appliesTo	molecular electronic states → nonlinear molecules →
assumes	molecular Hamiltonian invariant under point group operations →
characterizes	symmetry properties of degenerate electronic states →
concerns	symmetry of electronic wavefunctions → symmetry of nuclear configurations →
describes	relationship between molecular symmetry and electronic state degeneracy →
domain	chemical physics → quantum chemistry →
explains	conditions for occurrence of Jahn–Teller effect → origin of Jahn–Teller distortions in terms of symmetry →
field	group theory in chemistry → molecular quantum mechanics → molecular symmetry → theoretical chemistry →
historicalContext	developed in the 20th century →
implies	degenerate electronic states are associated with non-totally symmetric irreducible representations → degenerate electronic states in nonlinear molecules are unstable with respect to symmetry-lowering distortions →
influenced	applications of group theory in chemistry → development of modern Jahn–Teller theory →
involves	Born–Oppenheimer approximation → electronic Hamiltonian symmetry → nuclear configuration space →
isPartOf	molecular symmetry theory → theory of Jahn–Teller effect →
namedAfter	Hugh Christopher Longuet-Higgins →
relatedTo	Wigner’s theorem on degeneracies → group-theoretical treatment of molecular vibrations →
relatesTo	Jahn–Teller effect → electronic state degeneracies → symmetry-induced degeneracy → vibronic coupling →
usedFor	analyzing symmetry breaking in molecules → classifying electronic states by symmetry → predicting possible degeneracies of electronic states →
usesConcept	degenerate irreducible representations → irreducible representations → point group symmetry →

Referenced by (1)

Subject (surface form when different)	Predicate
Christopher Longuet-Higgins →	notableWork