Antimagnetic rotation in the shape-phase transition point nucleus 82Kr

The quadrupole transition strength B ( E 2) deduced from the measured level lifetimes using the Doppler shift attenuation method with the help of the Indian National Gamma Array, decreases with increasing spin for the band of interest in 82 Kr. In addition, the ratio of the dynamic moment of inertia with the B ( E 2) value increases along the band. Large basis shell -model calculations have been performed to understand the microscopic origin of the band of interest. The experimental results are reproduced well by the numerical calculations within the framework of a semiclassical geometric model, which conclusively establish the antimagnetic rotation in the shape -phase transition point nucleus 82 Kr in the A approximate to 80 mass region. Present investigation represents the first conclusive evidence of an antimagnetic rotational band based on the valence protons and neutrons in the 1 g 9 / 2 orbitals in an atomic nucleus.