A broken-pair description of89Y,91Nb and93Tc

Abstract

The low-energy properties of 89y, 91Nb and 93Tc are described in a broken-pair model. The shell model space for the protons consists of one major shell and for the neutrons particle-hole states within two major shells are taken into account. The effective interaction is assumed to be a simple Gaussian Serber force, which has proved to be the most successful in adjacent even nuclei. Energy spectra up to about 3 MeV excitation energy and one-nucleon transfer data can be described very well. Also electromagnetic properties can be reproduced rather well if reasonable effective charges are used. No indication for deformed states, as found in Sn nuclei, is observed.

Inelastic Electron Scattering From Nuclei

“…Using the value BIB = -0.069 calculated by Hofstra & Allaart (57) and taking the ratio of the densities in 90Zr and 89y (see Figure 11), one finds (A -,1)/(A +.4) = 0.48 ± 0.07, which yields AlA = 0.35 ± 0.05.3 This number is independent of a possible quenching of the current as long as the quenching is the same in 89y and 90Zr. Model calculations give for this ratio 0.09-RPA (55), 0.22-SM (56), and 0.29-Broken Pair (57). The RPA calculations do not include the pairing distribution explicitly.…”