Generator coordinate calculations on 28Si

The spectrum of 28Si is calculated by the generator coordinate method for various choices of generating functions obtained by solving the HF equations within the s-d shell with a constraint on the quadrupole or the hexadecapole moment, or with a constraint of the Holzwarth-Yukawa type. The influence of the symmetry of the generating functions is studied. The spectrum if quite sensitive to the choice of generator coordinate. A comparison with the shell-model calculations of Soveur and Zuker, and of Whitehead and Watt, is attempted. (Auth.)