Electric moments of the first excited state of 18O

Abstract

The static quadrupole moment Q 2 + and the B(E2; 0 + → 2 +) value of the first excited state of 18O at e x = 1.982 MeV have been determined using the reorientation effect in Coulomb excitation. Surface-barrier detectors at laboratory angles of 90° and 174° were used to detect 18O ions elastically and inelastically scattered from 208Pb. At both angles, we determined experimentally the maximum bombarding energies at which nuclear interference effects were negligible. It is found that Q + = −0.023 ± 0.021 e · b (−0.052 ± 0.021 e · b) for destructive (constructive) interference from higher states. This result is in good agreement with theoretical expectation. For the transition moment we find B(E2; 0 + → 2 +) = 0.00390 ± 0.00018 e 2 · b 2 (0.00371 ± 0.00018 e 2 · b 2) for destructive (constructive) interference.