[en] Difficulties in performing the calculations of E2, M1 matrix elements and incoherences in existing literature are reported for the mixing of bands with several valence nuclei. Various prescriptions may lead to rather different results: an illustration is given for the ²³Na nucleus

No abstract available

[en] We investigate the effects of a magnetic field with low to intermediate strength on several spectroscopic properties of the sodium atom. A model potential is used to describe the core of sodium, reducing the study of the system to an effective one-particle problem. All states with principal quantum numbers n = 3, 4, 5, 6 and 7 are studied and analysed. A grid of twenty values for the field strength in the complete regime B = 0-0.02 a.u. is employed. Ionisation energies, transition wavelengths and their dipole oscillator strengths are presented. (authors)

[en] Published in summary form only

[en] Doubly quantized vortices were topologically imprinted in vertical bar F=1> Na²³ condensates, and their time evolution was observed using a tomographic imaging technique. The decay into two singly quantized vortices was characterized and attributed to dynamical instability. The time scale of the splitting process was found to be longer at higher atom density

[en] We describe our experimental apparatus for quickly producing large Bose-Einstein condensates of ²³Na atoms. We collect atoms in a dark magneto-optical trap from a zero-crossing Zeeman slower and then capture the atoms in an optically plugged magnetic quadrupole trap and apply rf evaporation to cool the atoms into the quantum degenerate regime. We slightly displace a circular plug beam from the magnetic trap center to break the ring symmetry and form a single global minimum in the combined trapping potential. Our system reliably generates a quasipure condensate with over 10⁷ atoms every 17 s. We load the condensate into an elongated optical dipole trap.

No abstract available

[en] We have resolved closely spaced hyperfine levels in the 3P_3/2 state of ²³Na with a technique of coherent-control spectroscopy that uses co-propagating beams. The probe beam is locked to one hyperfine transition, while the control beam is scanned across a neighbouring transition. An acousto-optic modulator placed in the path of the control beam provides calibrated frequency offsets for measuring the hyperfine intervals. We thus obtain precise values for the hyperfine constants in the 3P_3/2 state: A 18.530(3) MHz and B = 2.721(8) MHz, which improve previous values significantly

[en] ¹²C(¹²C,pγ)²³Na proton-γ angular correlations were measured at E/subB/=38.82 MeV for the 9.042- and 9.805-MeV states in ²³Na which decay to levels at 7.270, 6.235, and 5.534 MeV with branching ratios of 20%, 60%, and 20%, respectively, for the 9.042-MeV state, and 30%, 50%, and 20%, respectively, for the 9.805-MeV state. Angular correlations and lifetime data eliminate 17/2 assignments for either state

[en] ²³Na nuclear magnetic resonance (NMR) measurements on poly (propylene oxide) (PPO) and siloxane based polymer electrolytes containing various sodium salts at a single nominal concentration are reported. In addition, differential scanning calorimetry (DSC) and electrical conductivity studies were carried out on the PPO materials. The NMR-determined mobile Na⁺ concentrations and DSC results provide evidence for ionic aggregation effects which, for some samples, result in salt precipitation at elevated temperatures. ²³Na chemical shifts observed in solid state NMR due to mobile Na⁺-anion interactions influence ionic transport as well as the number of available carriers. (author). 19 refs.; 7 figs