Experimental determination of the electric quadrupole moment of the first excited state of ¹⁹²Pt

Abstract

Coulomb excitation by ⁴He, ¹²C and ¹⁶O projectiles has been used to determine the static ¹⁶²Dy deduced yrast γ-transition characteristics. electric quadrupole momet 0(2⁺₁) of the first excited state of ¹⁹²Pt, together with the value of B(E2; 0⁺₁ → 2⁺₁). As with ^194,196,198pt, it is found that Q(2₁⁺) for ¹⁹²Pt is clearly positive, having the value 0.55 (21) e · b. The value obtained for $\text{B(}\text{E}\text{2; 0}{}_1{}^{\mathrm{+}}\text{→}{}^{\mathrm{+}}{}_1\text{)}\text{is}\text{1.833 (20) e}{}^2\text{b}{}^2$. The result obtained for Q(2₁⁺) supports the view that the prolate-to-oblate transition in the platinum isotopes is quite different from that in the osmium isotopes. The shape change is more sensitive to Z than N. The results are compared with the predictions of various nuclear models.