The low-lying yrast states in the 51 Ca and 52 Sc nuclei were investigated to obtain information on the evolution of the p 1 / 2 and f 5 / 2 neutron single-particle orbitals in neutron-rich nuclei near proton number Z = 20. Level structures associated with neutron excitations into these two orbitals and with proton excitations across the Z = 20 shell gap were identified. Shell-model calculations with the recently proposed GXPF1A interaction account reasonably well for the fp -shell states. The energy separation between the νp 1 / 2 and νf 5 / 2 orbitals in the Ca isotopes appears to be overestimated by the GXPF1A Hamiltonian. ispartof: Physical Review C, Nuclear Physics vol:77 issue:1 status: published