Publications by authors named "N de Ruette"

Article Synopsis
  • Negative ions play a crucial role in various scientific fields such as interstellar chemistry and anti-matter research, where their unique properties are influenced by electron-correlation effects.
  • Traditional methods for studying these ions face challenges due to their loosely bound nature and limited optical transitions, hindering high-resolution detection techniques.
  • A new method has been developed that accurately measures negative ion binding energies with significantly higher precision, utilizing laser manipulation and a cryogenic ion-beam storage ring, leading to a reported electron affinity of 1.461 112 972(87) eV for oxygen.
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We report absolute integral cross section (ICS) measurements using a dual-source merged-fast-beams apparatus to study the titular reactions over the relative translational energy range of Er ∼ 0.01-10 eV. We used photodetachment of C- to produce a pure beam of atomic C in the ground electronic 3P term, with statistically populated fine-structure levels.

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Article Synopsis
  • Researchers at Stockholm University's DESIREE facility measured the cooling lifetimes and detachment energies for three sizes of carbon anions (C3, C4, and C5) in a super-cool environment with low pressure.
  • They created two-dimensional photodetachment spectra that showed how the anions lost energy over time, revealing cooling lifetimes of 3.1 s, 6.8 s, and 24 s for each respective anion size.
  • The study's findings confirmed the occurrence of radiative cooling and established a model for simulating cooling dynamics, which could be useful for exploring other molecular anions in future research.
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We have measured fragment mass spectra and total destruction cross sections for protonated and deprotonated adenine following collisions with He at center-of-mass energies in the 20-240 eV range. Classical and ab initio molecular dynamics simulations are used to provide detailed information on the fragmentation pathways and suggest a range of alternative routes compared to those reported in earlier studies. These new pathways involve, for instance, losses of HNC molecules from protonated adenine and losses of NH or CHN from deprotonated adenine.

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We have measured total absolute cross sections for the mutual neutralization (MN) of O^{-} with O^{+} and N^{+}. A fine resolution (of about 50 meV) in the kinetic energy spectra of the product neutral atoms allows unique identification of the atomic states participating in the mutual neutralization process. Cross sections and branching ratios have also been calculated down to 1 meV center-of-mass collision energy for these two systems, with a multichannel Landau-Zener model and an asymptotic method for the ionic-covalent coupling matrix elements.

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