High spin structure of 84Y.

Abstract

The high spin levels of $^{84}\mathrm{Y}$ have been established up to 12 MeV excitation energy and probable spin of ${25}^{+}$ through the reaction $^{59}\mathrm{Co}$${(}^{28}$Si,2pn${)}^{84}$Y using in-beam \ensuremath{\gamma}-ray spectroscopic techniques. The \ensuremath{\gamma} transitions in $^{84}\mathrm{Y}$ have been identified through the particle-gamma coincidences. The level scheme was constructed through the \ensuremath{\gamma}-\ensuremath{\gamma} coincidences, angular distribution, and directional correlation orientation ratios. The positive parity yrast band built on the (\ensuremath{\pi}${\mathit{g}}_{9/2}$\ensuremath{\bigotimes}\ensuremath{\nu}${\mathit{g}}_{9/2}$) configuration shows a large signature splitting and a signature inversion at I\ensuremath{\sim}11\ensuremath{\Elzxh}. The measured B(E2; I\ensuremath{\rightarrow}I-2) values give a deformation ${\mathrm{\ensuremath{\beta}}}_{2}$\ensuremath{\sim}0.17. The negative parity band shows a signature inversion at I\ensuremath{\sim}11\ensuremath{\Elzxh} and B(M1; I\ensuremath{\rightarrow}I-1) enhancement for Ig11\ensuremath{\Elzxh}. The projected Hartree-Fock and the cranked shell model calculations provide an understanding for the observed properties of the energy levels in $^{84}\mathrm{Y}$.