Ion trap nuclear resonance on $\mathsf{^{151}Eu^ + }$

Laser-microwave double resonance techniques applied to a cloud of a natural mixture of Eu ⁺ isotopes confined in a Penning trap has been used to induce and detect nuclear Zeeman transitions. In spite of the complex level structure of Eu ⁺ and overlapping spectra from the two isotopes five different transitions could be observed from which the nuclear magnetic moment can be derived. We obtain for ¹⁵¹ Eu ⁺ g _I = 1.377 34(6) demonstrating the potential for high accuracy of the technique. The experiment can be considered as a feasibility test that precise spectroscopy data using the ion storage technique can be obtained of very complex ions and under unfavourable conditions.Received: 13 June 2003, Published online: 12 August 2003PACS: 32.60. + i Zeeman and Stark effects - 32.10.Dk Electric and magnetic moments, polarizability     

Feshbach resonances in $\mathsf{^{23}}$Na- $\mathsf{^{87}}$Rb

We describe s-wave collisions between ultracold ²³Na and ⁸⁷Rb atoms in the presence of a magnetic field. For any collision input channel knowledge of the singlet and triplet intermolecular potentials [1] enables us to predict the variation in scattering lengths as a function of the magnetic field. We employ the Born-Oppenheimer approximation to predict several Feshbach resonances for ²³Na⁸⁷Rb. We also include a discussion of why these resonances are expected to be narrow as observed in the case of ⁸⁷Rb₂.Received: 6 August 2004, Published online: 23 November 2004PACS: 34.90. + q Other topics in atomic collisions - 03.75.Hh Multicomponent condensates