Static Quadrupole Moment of the First Excited State of 28Si

Abstract

The reorientation effect in Coulomb excitation has been used to measure the static quadrupole moment Q2+ and B(E2;0+->2+) for the 1·779 MeV first excited state of 28Si. The results obtained are Q2+ = +15·5±3·4 efm 2 and B(E2;0+->2+) = 326±20 e 2 fm 4 • The value obtained for Q2+ confirms the results of other recent determinations using the reorientation effect, and the B(E2; 0+ -> 2 +) value is in excellent agreement with the mean value deduced from previous lifetime determinations. Shell model and Hartree-Fock calculations of Q2+ both give a good account of the experimental result.

Coulomb excitation of Ru102 with C12 and Garrett1, Zielińska2, Bergmaier3 et al. 2022Phys. Rev. C

“…The usual condition applied to ensure purely electromagnetic interactions is that the distance of closest approach of the nuclear surfaces s should be 5 fm. However, as has been previously investigated [35][36][37][38][39][40][41][42][43], this does not apply for relatively light ions such as 12 C and 16 O, for which nuclear effects have been observed at distances beyond 5 fm. We therefore followed, in the initial analysis, a conservative approach of adopting s = 6.5 fm as the minimum separation distance.…”

Role of hexadecapole deformation of projectile Si28 in heavy-ion fusion reactions near the Coulomb barrier

“…[22], as is shown by the dashed line with crosses. On the other hand, when the quadrupole deformation of 28 Si was taken to be positive, the shape of fusion barrier distribution becomes inconsistent with the experimental data (see the dashed line with triangles), supporting an oblate deformation of 28 Si [23]. The solid line in the figure shows the result with the vibrational excitation 28 Si, in which the first 2 + state is treated as a one phonon state in the harmonic oscillator approximation.…”