Mass spectrometry
He tagging maps copper cluster ion shapes
Open access · cc by · source: Europe PMC
Helium nanodroplet mass spectrometry of 63Cu clusters shows magic He shells that match computed binding sites, including twisted-X Cu5+.
How this study connects
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Evidence for the claim as stated.
Helium nanodroplet mass spectrometry of 63Cu clusters shows magic He shells that match computed binding sites, including twisted-X Cu5+.
Evidence for the claim as stated.
Soft ionisation preserves complexes that harsh ionisation destroys; imaging spatial resolution and native versus denaturing conditions are different experiments.
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
Soft ionisation preserves complexes that harsh ionisation destroys; imaging spatial resolution and native versus denaturing conditions are different experiments.
Study at a glance
- Design
- Computational / modelling — He nanodroplet mass spectra of Cu clusters compared with MP2 He-binding calculations
- N
- Gas-phase cluster experiment plus theory — no sample N
- Population
- Copper cluster ions solvated by helium in nanodroplets
- Outcome
- Magic-number structures and He-shell closing around Cu_n^+/−
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Inspect source passages
He tagging maps copper cluster ion shapes
These passages occur verbatim in the stored paper text. They support the points listed below; they do not verify every statement in the explanation.
First He atoms on Cu+ bind by about 40 meV each (without ZPE).
The most tightly bound He atoms are found for the lone Cu + ion, where the first few He atoms are bound by approximately 40 meV each (without correcting for the zero-point energy, ZPE).
The trigonal bipyramid lies about 70 meV above the twisted-X geometry.
The prior lies approximately 70 meV higher in energy compared to the twisted-X geometry while the latter forms an unstable transition state in the electronic ground state, as do all attempts that we have made to produce a planar structure.
Key findings
Cu+ closes a shell at 6 He (octahedron). Cu5+ is the smallest 3D cluster, twisted-X, with a strong m = 4 magic number (~70 meV above a bipyramid). Anions bind more He at similar pressures.
Methodology
Authors ionized He nanodroplets, picked up monoisotopic 63Cu, evaporated with He gas, and compared magic He_mCu_n^+/− intensities with MP2 He-binding calculations.
Limitations
Structures are inferred from tagging, not a crystal; large-m magic numbers are noisy; anions have isobaric impurity risks at m = 7, 9.
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