Excitation and decay of the first excited state of17Ne

The first excited state of {sup 17}Ne has been populated via relativistic Coulomb excitation with a radioactive beam of {sup 17}Ne on a {sup 197}Au target and the subsequent {gamma}-ray decay has been observed. This (3)/(2){sup {minus}} state is bound with respect to proton emission but unbound to two-proton decay. The measured {gamma}-ray yield accounts for 43{sub {minus}14}{sup +19}{percent} of the predicted yield from an excitation cross section of 28 mb. It is unlikely that the missing cross section can be attributed to two-proton emission because the lifetime of this branch would have to be a factor 1700 smaller than predicted by standard barrier penetration calculations. {copyright} {ital 1997} {ital The American Physical Society}