Spectroscopic studies of the beta decay of I-140 have firmly established oc
tupole collectivity in Xe-140 and evinced unique theoretical predictions of
a quenched dipole moment. The first detailed investigations of an exotic X
e nucleus, including measurements of half-lives of levels in the ground and
octupole bands, were made possible due to a new approach to produce beams
of iodine with ISOL sources.