A calculation of the odd parity spectrum of¹⁶O and⁴⁰Ca from the interaction between nucleons: Method and first results

Abstract

In the framework of an exact many-body theory based on the formalism of Green's functions, we rederive an eigenvalue equation capable of describing single particle excitations of a Fermi system. The effective two-particle interaction entering this equation is extracted free of all adjustable parameters from a very simple nucleon-nucleon interaction by solving the corresponding integral equation for nuclear matter and using a local density approximation. We apply our method for describing those states of the doubly magic nuclei¹⁶O and⁴⁰Ca which probably can be understood as one-particle-one-hole excitations from the ground state, i.e. low-lying negative parity levels, and — in view of the simplicity of the interaction assumed — find reasonably good aggreement with experimental evidence.