- published: 27 Oct 2014
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An excimer (originally short for excited dimer) is a short-lived dimeric or heterodimeric molecule formed from two species, at least one of which is in an electronic excited state. Excimers are often diatomic and are composed of two atoms or molecules that would not bond if both were in the ground state. The lifetime of an excimer is very short, on the order of nanoseconds. Binding of a larger number of excited atoms form Rydberg matter clusters, the lifetime of which can exceed many seconds.
Under the molecular orbital formalism, a typical ground-state molecule has electrons in the lowest possible energy levels. According to the Pauli principle, at most two electrons can occupy a given orbital, and if an orbital contains two electrons they must be in opposite spin states. The highest occupied molecular orbital is called the HOMO and the lowest unoccupied molecular orbital is called the LUMO; the energy gap between these two states is known as the HOMO/LUMO gap. If the molecule absorbs light whose energy is larger than this gap, an electron in the HOMO may be excited to the LUMO. This is called the molecule's excited state.
My favourite thing to do
Is to dig bodies from the grave
I'm sure that you can see
That I'm sickening and crazed
Walking through the graveyard
With a shovel in my hand
Looking for a grave
I'm an exhumer of the dead
I'm digging up your grave
With a smile on my face
I'm sure you know my status
I'm a sickening disgrace
Taking off your jewellery
And having such a ball
I'll take it to the pawnshop
And I'll sell it fuckin' all