The decay of the first two excited states of ${}^{17}\mathrm{Ne}$ ${(I}^{\pi }={\frac{3}{2}}^{-},$ ${\frac{5}{2}}^{-})$ has been studied via intermediate energy Coulomb excitation of a radioactive ${}^{17}\mathrm{Ne}$ beam on a ${}^{197}\mathrm{Au}$ target using a particle detector setup allowing a kinematically complete detection of the reaction products. Despite the first excited state being bound to single proton emission but unbound with respect to two proton emission, no evidence for a simultaneous two proton decay competing with the known $\gamma$ decay of the ${\frac{3}{2}}^{-}$ state could be observed. The ${\frac{5}{2}}^{-}$ state decays via sequential two-proton emission to the ground state of ${}^{15}\mathrm{O}.$ The transition matrix elements $B(E2,{\frac{1}{2}}^{-}\to {\frac{3}{2}}^{-}{)=66\mathrm{}}_{-25}^{+18\mathrm{}}\hspace{0.5em}{e}^2{\mathrm{fm}}^4$ and $B(E2,{\frac{1}{2}}^{-}\to {\frac{5}{2}}^{-}{)=124\mathrm{}(18)e}^2{\mathrm{fm}}^4$ have been deduced. From the nonobservation of the simultaneous two-proton emission of the ${\frac{3}{2}}^{-}$ state a lifetime limit ${\tau }_{2p}>26\mathrm{}\hspace{0.5em}\mathrm{ps}$ could be deduced in agreement with recent theoretical calculations.

• Received 30 May 2002

DOI:https://doi.org/10.1103/PhysRevC.66.024313