Determination of Profile Parameters of an Atomic Resonance without Ultra-high Energy Resolution

T. K. Fang, T. N. Chang

A deconvolution procedure is proposed to determine the resonant width $\ensuremath{\Gamma}$, the asymmetry parameter $q$, and the background cross section ${\ensuremath{\sigma}}_{b}$ of a Fano-type resonance in the absence of an ultrahigh-energy resolution. This procedure enables a direct extrapolation to infinite energy resolution using a set of explicit analytical relations in terms of the ratio between the width $\ensuremath{\Gamma}$ and the experimental energy resolution $\ensuremath{\Omega}$ in the limit of $\ensuremath{\Gamma}/\ensuremath{\Omega}\ensuremath{\ll}1$.

R. Neugart, S. L. Kaufman, W. Klempt +3 more

秀一 長谷川

Andreas Sebastian Konig, Jörg Neukammer, H. Hieronymus +1 more

Stark spectra of barium Rydberg states above the classical field-ionization limit have been recorded at high density of states employing high-resolution laser spectroscopy. The spectra, taken at a binding energy of about \ensuremath{\varepsilon}\ensuremath{\approxeq}-55 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ with respect to zero-field threshold and at electric-field strengths F\ensuremath{\approxeq}100 V/cm exhibit dramatic variations in line profiles with increasing external field strength. The WKB quantum-defect theory of the Stark effect of nonhydrogenic atoms was used to analyze the recorded spectra, and excellent agreement between measured and calculated line profiles was achieved. Core-induced coupling of closed and open hydrogenic Stark channels was found to contribute dominantly to the linewidth of the recorded Stark resonances. In addition, a reformulation of this theory by McNicholl, Ivri, and Bergeman (unpublished) in terms of a configuration-interaction model was employed to analyze a particular avoided crossing of several Stark components. In this way recorded line profiles were parametrized within a limited model to obtain resonance energies, linewidths, and Fano q parameters.

Isidor Isaac Rabi

Andrew J. Kerman, Cheng Chin, Vladan Vuletić +4 more

Abstract : We measure high-resolution Feshbach resonance spectra for ultracold desium atoms colliding in different hyperfine and magnetic sublevels. More than 25 Feshback resonances are observed for magnetic fields below 230 G in the elastic and inelastic ground state collision cross sections, as well as in the cross section for light-assisted collisions. From thes spectra a consistent set of ground state molecular interaction parameters for desium is extracted, including singlet and triplet scattering lengths of As=(280 +/- 10)a) and At=(2400 +/- 100)a), a van der Waals coefficient C6=(6890 +/- 35) a.u., as well as the strength of the indirect spin-spin coupling. This set of parameters allows for the first time a complet characterisation of cesium's ultra-cold collision properties.