Radiative Width of Molecular-Cluster States

Molecular states are characterized by enhanced electromagnetic deexcitations of many different multipolarities. The expected enhancement of $E1\mathrm{}$, $E2\mathrm{}$, and $E3\mathrm{}$ transitions is examined deriving molecular sum rules for radiative deexcitation widths and via a dimensionality approach. The enhancement of the $E1\mathrm{}$ transitions is the most striking.