Abstrakt
Background: A fairly rich amount of experimental spectroscopic data have disclosed intriguing properties of the nuclei in the region of neutron rich oxygen isotopes up to the neutron dripline. They, therefore, represent a unique laboratory for studying the evolution of nuclear structure away from the stability line.
Purpose: We intend to give an exhaustive microscopic description of low and high energy spectra, dipole response, weak, and electromagnetic properties of the even O-22 and the odd O-23 and F-23. Method: An equation of motion phonon method generates an orthonormal basis of correlated n-phonon states (n = 0,1,2,...) built of constituent Tamm-Dancoff phonons.
This basis is adopted to solve the full eigenvalue equations in even nuclei and to construct an orthonormal particle-core basis for the eigenvalue problem in odd nuclei. No approximations are involved and the Pauli principle is taken into full account.
The method is adopted to perform self-consistent, parameter free, calculations using an optimized chiral nucleon-nucleon interaction in a space encompassing up to two-phonon basis states. Results: The computed spectra in O-22 and O-23 and the dipole cross section in O-22 are in overall agreement with the experimental data.
The calculation describes poorly the spectrum of F-23. Conclusions: The two-phonon configurations play a crucial role in the description of spectra and transitions.
The large discrepancies concerning the spectra of F-23 are ultimately traced back to the large separation between the Hartree-Fock levels belonging to different major shells. We suggest that a more compact single particle spectrum is needed and can be generated by a new chiral potential which includes explicitly the contribution of the three-body forces.