Lifetime measurements in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mmultiscripts><mml:mi>Mo</mml:mi><mml:mprescripts/><mml:none/><mml:mn>92</mml:mn></mml:mmultiscripts></mml:math>: Investigation of seniority conservation in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>N</mml:mi><mml:mo>=</mml:mo><mml:mn>50</mml:mn></mml:mrow></mml:math> isotones
M. Ley, L. Knafla, J. Jolie, A. Esmaylzadeh, A. Härter, A. Blazhev, C. Fransen, A. Pfeil, J.-M. Régis, P. Van Isacker
Abstract
Excited states in the yrast and negative parity bands in $^{92}\mathrm{Mo}$ were populated in two different experiments using the $^{90}\mathrm{Zr}(\ensuremath{\alpha},2n)^{92}\mathrm{Mo}$ and $^{93}\mathrm{Nb}(p,2n)^{92}\mathrm{Mo}$ fusion-evaporation reactions at the Cologne FN Tandem accelerator and measured using a hybrid setup of high purity germanium and lanthanum bromide detectors. Lifetimes of the excited ${2}_{1}^{+}, {4}_{1}^{+}, {6}_{1}^{+}, {8}_{1}^{+}, {5}_{1}^{\ensuremath{-}}, {7}_{1}^{\ensuremath{-}}$, and ${9}_{1}^{\ensuremath{-}}$ states were measured using the $\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}$ fast-timing technique. The newly measured lifetime of the ${4}_{1}^{+}$ state differs from the recently published value measured using the recoil distance Doppler shift method. Experimental $B(E2)$ strengths of excited states in $^{92}\mathrm{Mo}$ are used to predict theoretical $B(E2)$ values in the $N=50$ isotones from $^{93}\mathrm{Tc}$ up to $^{95}\mathrm{Rh}$ using semiempirical calculations in the single-$j$ orbital $0{g}_{9/2}$ for the protons.