In the context of chemistry, the term refers to the representation of the electronic
structure of a
molecular entity in terms of
contributing structures. Resonance among contributing structures means that the wavefunction is represented
by '
mixing' the wavefunctions of the contributing structures. The concept is the basis of the
quantum mechanical
valence bond methods. The resulting stabilization is linked to the quantum mechanical concept
of '
resonance energy'. The term resonance is also used to refer to the
delocalization phenomenon itself.
Source:
PAC, 1994, 66, 1077
(Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994))
on page 1161