Elementary Modes of Excitation: Particle-Hole Excitations at Closed Shells

Abstract

Having derived in the final part of Chap. 5 the second quantized expression for the nuclear many-body Hamiltonian (containing one-body and two-body operators), we shall now study how elementary excitations of the doubly-closed shells, via particle-hole excitations, can give rise to the low-lying excited states that have been observed in these nuclei. In this chapter we shall describe the basic methods of treating the residual interactions, induced by the Hamiltonian of (5.92), in doubly-closed shell nuclei. In addition to approximation methods that highlight the salient features of these elementary excitation modes (exactly solvable models), we shall also discuss a realistic application to the case of ¹⁶O as a doubly-closed shell nucleus.