Characterization of the “three-phonon” region of 100Ru

Abstract Lifetimes of excited states in 100 Ru were determined from Doppler-shift attenuation measurements following the 100 Ru(n, n ′ γ ) reaction. Absolute transition rates or limits thereon were extracted for states in the three-phonon region and were compared with an interacting boson model description of this nucleus. Intruder states were identified, and a candidate for the 2 + mixed-symmetry state is suggested.