The binding energy and fine-structure splitting of the ground state of the ${\mathrm{Sr}}^{\mathrm{\ensuremath{-}}}$n(${5\mathrm{s}}^{2}
5p{\mathrm{}}^{2}$P) ion have been measured by means of the laser photodetachment threshold technique combined with state-selective detection of neutral atoms using resonant ionization spectroscopy. We find binding energies of 32.17\ifmmode\pm\else\textpm\fi{}0.03 meV (J=3/2) and 52.06\ifmmode\pm\else\textpm\fi{}0.06 meV (J=1/2), yielding a fine-structure splitting of 19.89\ifmmode\pm\else\textpm\fi{}0.07 meV. This represents an improvement of two orders of magnitude compared to the recent data based on a combination of laser photodetachment and accelerator mass spectroscopy [D. Berkovits et al., Phys. Rev. Lett. 75, 414 (1995)].
The electron affinity of thulium has been measured using laser photodetachment electron spectroscopy. The electron affinity of
Tm(2F7/2) was determined to be $1.029\ifmmode\pm\else\textpm\fi{}0.022\mathrm{eV}.$ The data also show that ${\mathrm{Tm}}^{\mathrm{\ensuremath{-}}}$ has at least one bound excited state with a binding energy of $0.979\ifmmode\pm\else\textpm\fi{}0.017\mathrm{eV}$ relative to the ground state of the thulium atom. The present experimental measurements are compared to a recent calculation of the electronic structure of ${\mathrm{Tm}}^{\mathrm{\ensuremath{-}}}$ and a recent experimental investigation of ${\mathrm{Tm}}^{\mathrm{\ensuremath{-}}}.$
Negative ions are unique quantum systems where electron correlation plays a decisive role in determining their properties. The lack of optically allowed transitions prevents traditional optical spectroscopy and the electron affinity is, therefore, for most elements, the only atomic quantity that can be determined with high accuracy. In this work, we present a high-precision experimental determination of the electron affinity of cesium. A collinear laser-ion beam apparatus was used to investigate the partial photodetachment cross section for the cesium anion, leaving the neutral atom in the 6p 2P3/2 excited state. A resonance ionization scheme was used to obtain final-state selectivity, which enabled the investigation of a sharp onset of the cross section associated with a Wigner s -wave threshold behavior. The electron affinity was determined to be 0.4715983(38)eV . Published by the American Physical Society 2024
Abstract Negative ions, which are formed when an electron is attached to a neutral system, are unique quantum systems. The lack of a long-range Coulomb force causes the inter-electronic interactions to become relatively more important. As a consequence, the independent particle model, which adequately describes atomic structure under normal conditions, breaks down. The alkali negative ions, with a closed valence s-shell, are among the simplest anionic systems. Hence, they can favorably be used to benchmark atomic theory. In this work, we have determined the electron affinity of 85Rb by measuring the relative partial photodetachment cross section of the negative ion, leaving the residual atom in the 5p 2 P 3 / 2 excited state. Resonance ionization spectroscopy allows for state selectivity and the ability to measure the Wigner s-wave threshold onset of the photodetachment process. The electron affinity of 85Rb was determined to be 485.887(6) meV.
We have investigated the threshold of photodetachment of ${\mathrm{Li}}^{\mathrm{\ensuremath{-}}}$ leading to the formation of the residual Li atom in the 2
p2P state. The excited residual atom was selectively photoionized via an intermediate Rydberg state and the resulting
Li+ ion was detected. A collinear laser-ion beam geometry enabled both high resolution and sensitivity to be attained. We have demonstrated the potential of this state-selective photodetachment spectroscopic method by improving the accuracy of Li electron affinity measurements an order of magnitude. From a fit to the Wigner law in the threshold region, we obtained a Li electron affinity of 0.618 049(20) eV. \textcopyright{} 1996 The American Physical Society.
Using new experimental measurements of photoassociation resonances near the
1S0→3P1 intercombination transition in
84Sr and
86Sr, we present an updated study into the mass-scaling behavior of bosonic strontium dimers. A previous mass-scaling model [Borkowski et al., Phys. Rev. A 90, 032713 (2014)] was able to incorporate a large number of photoassociation resonances for
88Sr, but at the time only a handful of resonances close to the dissociation limit were known for
84Sr and
86Sr. In this work, we perform a more thorough measurement of
84Sr and
86Sr bound states, identifying multiple new resonances at deeper binding energies out to
E/h=−5 GHz. We also identify several previously measured resonances that cannot be experimentally reproduced and provide alternative binding energies instead. With this improved spectrum, we develop a mass-scaled model that reproduces the observed binding energies of
86Sr and
88Sr to within 1 MHz. In order to accurately reproduce the deeper bound states, our model includes a second
1u channel and more faithfully reproduces the depth of the potential. As determined by the previous mass-scaling study,
84Sr
0u+ levels are strongly perturbed by the avoided crossing between the
1S0+3P1 0u+ (3Πu) and
1S0+1D2 0u+ (1Σu+) potential curves and therefore are not included in this mass-scaled model, but are accurately reproduced using an isotope-specific model with slightly different quantum defect parameters. In addition, the optical lengths of the
84Sr
0u+, ν=−2 to
ν=−5 states are measured and compared to numerical estimates to characterize their use as optical Feshbach resonances.