Multiple Coulomb excitation interpretation of the 70Ge beam and the interpretation of the O2+ as a deformed intruder

Electromagnetic properties of the low-lying states in a Ge-70 nucleus were studied through the multiple Coulomb excitation of a Ge-70 beam with a Pb-nat target. Relative gamma-ray intensities were measured as a function of emission angle relative to the scattered projectile. Sixteen E2 matrix elements, including diagonal ones, for 6 low-lying states have been determined using the least-squares search code GOSIA. The expectation values <Q(2)> of 0(1)(+) and 0(+)(1) states in Ge-70 are compared with those in Ge-72,Ge-74,Ge-76. Simple mixing calculations indicate that the 0(2)(+) states in Ge-70 and Se-72 can be treated as deformed intruder states. It is shown that the deformed intruder becomes the ground state in Kr-74. These interpretations of the 0(2)(+) states in this region are compared with the potential-energy surface calculations by the Nilsson-Strutinsky model, which allow to interpret the experimental results in a qualitative way from the theoretical point of view.