Evidence for very large deformation in neutron deficient nuclei with Zapprox. =40

A detailed study of very neutron deficient nuclei with Zapprox. =40 (Sr,Zr) and Napprox. =40 has been carried out. Total potential energy surfaces taking into account both quadrupole and hexadecapole deformation have been calculated for the Zr (Z = 40) nuclei, starting from the Nilsson model. Also odd-mass nuclei have subsequently been studied when coupling the odd particle to the deformed even-even core. After extensive band mixing calculations for the 3879Sr41 nucleus, comparison to the existing experimental data [energy spectra for positive and negative parity (5/2)+[422] and (3/2)-[301] bands; static moments μ,Q; mixing ratios delta(E2/M1) and branching ratios] has been carried out. We have also concentrated on the excited state properties of even-even Sr nuclei within the framework of the interacting boson model. A critical analysis of the interacting boson model parameters, as obtained from calculations in nearby nuclei, i.e., 34Se, 36Kr, is carried out, especially for the behavior of kappa, chi/sub π/, and chi/sub ν/