Reposting from another section... Can anyone explain to me how an excimer is formed? Like structure wise? Considering Xenon. I've gathered that an excited state Xe*, ground state Xe, and a 3rd body M react resulting in an Xe* excimer + M(carrying away excess energy). I'm struggling to find how the ground state Xe can have any reaction at all with its full valence band. Any pointers? Thanks in advance! PS My physics/chemistry isn't particularly advanced, I'm studying elec. engineering.