Observation of a strong correlation betweeng(2⁺γvib) andg(2⁺rot) in strongly deformed nuclei

Abstract

The E2/M1 multipole mixing parameters of cascade transitions inγ-vibrational bands of¹⁵⁴Gd,¹⁶⁶Er and¹⁶⁸Er have been determined byγ-γ directional correlation measurements as:

$$\begin{array}{l} \delta \left( {^{154} Gd\left( {3_\gamma ^ + \to 2_\gamma ^ + } \right)} \right) = - 4.3_{ + 2.1}^{ - 9.4} \\ \delta \left( {^{166} Er\left( {5_\gamma ^ + \to 4_\gamma ^ + } \right)} \right) = + 1.94_{ - 0.21}^{ + 0.23} \\ \end{array}$$

and

$$\delta \left( {^{168} Er\left( {3_\gamma ^ + \to 2_\gamma ^ + } \right)} \right) = + 1.42_{ - 0.04}^{ + 0.04} $$

(with conversion data [15] taken into account)

These data were used to deriveg(2⁺ γvib)−g(2⁺rot). The results, together withg-factors derived from direct measurements by IPAC and Mössbuer spectroscopy [10] or by use of transient fields [9, 31] exhibit a strong correlation between bothg-factors, i.e. ifg(2⁺rot) is largeg(2⁺ γvib) is small and vice versa. The most direct and most simple interpretation is the assumption of a more or less different density distribution of protons and neutrons in the nuclei.