  The technique of recoil beta tagging has been developed which allows prompt
gamma decays in nuclei from excited states to be correlated with electrons from
their subsequent short-lived beta decay. This technique is ideal for studying
nuclei very far from stability and improves in sensitivity for very short-lived
decays and for high decay Q-values. The method has allowed excited states in
78Y to be observed for the first time, as well as an extension in the knowledge
of T=1 states in 74Rb. From this new information it has been possible to
compare Coulomb energy differences (CED) between T=1 states in 70Br/70Se,
74Rb/74Kr, and 78Y/78Sr. The A=70 CED exhibit an anomalous behavior which is
inconsistent with all other known CED. This behavior may be accounted for
qualitatively in terms of small variations in the Coulomb energy arising from
shape changes.
