LAUSR

We construct an effective shell-model interaction for the valence space spanned by single-particle neutron and single-hole proton states in Sn. Starting from chiral nucleon-nucleon and threenucleon forces and single-reference coupled-cluster theory for Sn we apply a second similarity transformation that decouples the valence space. The particle-particle components of the resulting effective interaction can be used in shell model calculations for neutron deficient tin isotopes. The hole-hole interaction can be used to calculate the N = 50 isotones south of Sn, and the full particle-hole interaction describes nuclei in the region southeast of Sn. We compute low-lying excited states in selected nuclei southeast of Sn, and find reasonable agreement with data. The presented techniques can also be applied to construct effective shell-model interactions for other regions of the nuclear chart.