Transition quadrupole moments of high-spin states in 170W

Abstract

Lifetimes of states in 170W have been measured by the Doppler-shift recoil-distance and Doppler-broadened line-shape (DBLS) methods using the reaction 122Sn( 52Cr, 4n) 170W at a bombarding energy of 230 MeV. The data were collected in the γγ-coincidence mode in order to reduce the complexities of the γ-ray spectra and to avoid some of the problems associated with side-feeding to excited states. The experimental transition quadrupole moments, Q t, cluster around a value of 6 e · b up through spin of I = 24 h ̵ . This is the trend predicted by cranked Hartree-Fock-Bogoliubov (HFB) calculations and by the calculated systematics of triaxial-shape-driving forces which originate from the aligned i 13 2 neutron orbitals around N = 96. The interaction strength | V| between the g- and the s-band extracted from the data is 60±5 keV. The Q t values of several states in the negative-parity band (−, 1) also cluster around a value of 6 e · b. The El transition probabilities for the decay of states in the ( π, α) = (−, 1) band to states in the ground-state band range between 10 −5 to 3.5 × 10 −4 W.u.. The B(E1, I → + 1) is one order of magnitude larger than the B(E1, I → I − 1). The origin of these effects can probably be understood in terms of a predominant admixture of Coriolis-coupled octupole vibrational-state wave functions in the (−, 1) band of 170W at low spin.