a dimer formed through the bonding of an electrically excited molecule with an unexcited one: such a bond decays rapidly into a dissociative ground state, resulting in radiation emission
Origin of excimerexci(ted) (adjective) + (di)mer
A diatomic molecule that exists only when one of the atoms is in an excited energy state, especially one whose atoms are the same chemical element.
Origin of excimerexc(ited) (d)imer
exci- +"Ž -mer