3 research outputs found
Impact of buffer gas quenching on the S-1(0) -> P-1(1) ground-state atomic transition in nobelium
International audienceUsing the sensitive Radiation Detected Resonance Ionization Spectroscopy (RADRIS) techniquean optical transition in neutral nobelium (No, Z = 102) was identified. A remnant signal when delaying the ionizing laser indicated the influence of a strong buffer gas induced de-excitation of the optically populated level. A subsequent investigation of the chemical homologue, ytterbium (Yb, Z = 70), enabled a detailed study of the atomic levels involved in this process, leading to the development of a rate equation model. This paves the way for characterizing resonance ionization spectroscopy (RIS) schemes used in the studyof nobelium and beyond, where atomic properties are currently unknown
Online chemical adsorption studies of Hg, Tl, and Pb on SiO2 and Au surfaces in preparation for chemical investigations on Cn, Nh, and Fl at TASCA
Online gas-solid adsorption studies with single-atom quantities of Hg, Tl, and Pb, the lighter homologs of the superheavy elements (SHE) copernicium (Cn, Z =112), nihonium (Nh, Z =113), and flerovium (Fl, Z =114), were carried out using short-lived radioisotopes. The interaction with Au and SiO 2 surfaces was studied and the overall chemical yield was determined. Suitable radioisotopes were produced in fusion-evaporation reactions, isolated in the gas-filled recoil separator TASCA, and flushed rapidly to an adjacent setup of two gas chromatography detector arrays covered with SiO 2 (first array) and Au (second array). While Tl and Pb adsorbed on the SiO 2 surface, Hg interacts only weakly and reached the Au-covered array. Our results contribute to elucidating the influence of relativistic effects on chemical properties of the heaviest elements by providing experimental data on these lighter homologs
Atom-at-a-time laser resonance ionization spectroscopy of nobelium
Optical spectroscopy of a primordial isotope has traditionally
formed the basis for understanding the atomic structure of an
element. Such studies have been conducted for most elements1
and theoretical modelling can be performed to high precision2,3,
taking into account relativistic effects that scale approximately as
the square of the atomic number. However, for the transfermium
elements (those with atomic numbers greater than 100), the atomic
structure is experimentally unknown. These radioactive elements
are produced in nuclear fusion reactions at rates of only a few atoms
per second at most and must be studied immediately following their
production4, which has so far precluded their optical spectroscopy.
Here we report laser resonance ionization spectroscopy of nobelium
(No; atomic number 102) in single-atom-at-a-time quantities,
in which we identify the ground-state transition 1S0 → 1P1. By
combining this result with data from an observed Rydberg series,
we obtain an upper limit for the ionization potential of nobelium.
These accurate results from direct laser excitations of outer-shell
electrons cannot be achieved using state-of-the-art relativistic manybody
calculations5–8 that include quantum electrodynamic effects,
owing to large uncertainties in the modelled transition energies
of the complex systems under consideration. Our work opens the
door to high-precision measurements of various atomic and nuclear
properties of elements heavier than nobelium, and motivates future
theoretical work.
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