First Theoretical Identification of the Magnetic Dipole Moment of the Excited State at 97.43 keV in 153Eu

Abstract

Two alternative values, +3.21±0.22 μ_N and-0.52±0.22 μ_N, for the magnetic dipole (M1) moment of the excited [532] 5/2- state at 97.43 keV in 153Eu were reported in the Mossbauer-effect study. In order to determine the correct value of the magnetic moment of the 97.43 keV level of 153Eu nucleus, the Quasiparticle Phonon Nuclear Model (QPNM) has been used. According to the QPNM calculations experimental 97.43 keV level is the [532] 5/2- Nilsson state occurring at 79 keV. The magnetic moment of this state as calculated according to the QPNM is +3.2162 μ_N which agrees well with one of the experimental values, +3.21±0.22 μ_N. Therefore, the correct value for the magnetic moment of the 97.43 keV level of 153Eu is in our opinion +3.21±0.22 μ_N. The measured value (+3.4717±0.006 μ_N) of the magnetic moment of 5/2- ground-state of 151Eu which is also probably a [532] Nilsson state according to our QPNM calculations also support our prediction.