Negative-parity intruder states of the neutron-rich N=20, Z=14-16 isotones: a 1(h)over-barω shell model description

In order to get a consistent shell model description of the negative-parity states throughout the sd shell a new interaction (PSDPFB) has been developed. It was derived in the full p-sd-pf model space and is built on existing interactions for the major shells with adjustments of the cross-shell monopoles. The calculated energy spectra for these 1 (h) over bar omega intruder states are compared to experiment for the N = 20 neutron-rich isotones Si-34, P-35 and S-36. A systematics for the multiplet configuration nu(d(3/2)(-1)f(7/2)(1)) in even-even isotones from Si-34 to Ca-40 is also presented.