  We combine a recently developed ab initio many-body approach capable of
describing simultaneously both bound and scattering states, the ab initio
NCSM/RGM, with an importance truncation scheme for the cluster eigenstate basis
and demostrate its applicability to nuclei with mass numbers as high as 17.
Using soft similarity renormalization group evolved chiral nucleon-nucleon
interactions, we first calculate nucleon-4He phase shifts, cross sections and
analyzing power. Next, we investigate nucleon scattering on 7Li, 7Be, 12C and
16O in coupled-channel NCSM/RGM calculations that include low-lying excited
states of these nuclei. We check the convergence of phase shifts with the basis
size and study A=8, 13, and 17 bound and unbound states. Our calculations
predict low-lying resonances in 8Li and 8B that have not been experimentally
clearly identified yet. We are able to reproduce reasonably well the structure
of the A=13 low lying states. However, we find that A=17 states cannot be
described without an improved treatment of 16O one-particle-one-hole
excitations and alpha clustering.
