The quadrupole moment of the first excited state of l80

Using the re-orientation effect in Coulomb excitation, the quadrupole moment, Q2+, of the first excited state of "0 is found to be -0,100 0.030 eb. The analysis assumes, on the basis of previous measurements, that B(E2; 0' --f 2') = 0.0044 i 0.0004 e2b2. A correction (+0.032 eb) for the effect of the giant dipole resonance, based on the hydrodynamic model, has been applied. Evidence is presented that some other deter- minations of Q2+ were performed at too high a bombarding energy. The present value for Q2+ is smaller in magnitude than that reported by Kleinfeld et al, but remains larger than the value of -0.034 eb predicted by a recent shell-model calculation.