Indications of octupole correlation in ⁸⁴Sr

Abstract

Excited states in the 84 Sr nucleus were investigated via the
Ge( 12 C,4n) 84 Sr reaction at a beam energy of 58 MeV. The de-excited γ-rays were
detected using the Indian National Gamma Array (INGA) spectrometer at Inter-
University Accelerator Center, New Delhi. Directional Correlation from Oriented
(DCO) states ratio and the polarization asymmetry (∆) measurements were done to
confirm the spin-parity of the low-lying states. Eight new γ-ray transitions were placed
in the level scheme of 84 Sr. The systematic behaviour of energy staggering S(I) of the
γ-band (Band 1 and Band 2) was compared with the γ-bands in the mass A≈80 region
and the nuclei of other mass region with similar behaviour (odd-I down). The E1
character is confirmed for strong γ-ray transitions connecting Band 3 to Yrast band.
Comparison of new results such as B(E1)/B(E2) ratio, frequency ratio ω − /ω + and
energy displacement ∆E in 84 Sr with those of 72 Se, 150 Sm, 152 Gd, 220 Ra and 224 Th
nuclei suggests the presence of octupole correlations in 84 Sr.