RENAISSANCE OF THE NILSSON-MODEL APPROACH TO LIGHT-NUCLEI - THE CASE OF THE A=26 SYSTEM

The farthest reaching interpretation of a light nuclear system in term s of the Nilsson-model is obtained for A = 26. The T = 1 and T = 0 lev els of either parity in Mg-26 and/or Al-26 are shown to be grouped in more than 35 rotational bands together containing some 55 levels in Mg -26 and 170 in Al-26. The Nilsson-model configurations and deformation s of bands are deduced from measured spectroscopic factors and electro magnetic transition rates. The experimental data are amended by shell- model calculations in the complete s-d basis space based on the univer sal s-d Hamiltonian. The rotational structure of positive-parity state s is complexely contained in the shell-model results. The Nilsson diag ram gives a natural explanation of all bands. An important facet is th e observation of particle-hole configurations with large K which arise from the complete alignment of particle and hole angular momenta alon g the major axis of deformation. (C) 1998 Elsevier Science B.V.