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Updated: Jan 20, 2026

Reconstruction of Single-Cell Innate Fluorescence Signatures by Confocal Microscopy
Published on: May 27, 2020
Infrared Signatures of the HHe+ and DHe+ (n = 3-6) Complexes
Oskar Asvany1, Stephan Schlemmer1, Tamás Szidarovszky2
1I. Physikalisches Institut , Universität zu Köln , Zülpicher Str. 77 , 50937 Köln , Germany.
Abstract:
Combination of a cryogenic ion-trap machine, operated at 4.7 K, with the free-electron-laser FELIX allows the first experimental characterization of the unusually bright antisymmetric stretch (ν3) and π-bending (ν2) fundamentals of the He-X+-He (X = H, D) chromophore of the in situ prepared HHe+ and DHe+ (n = 3-6) complexes. The band origins obtained are fully supported by first-principles quantum-chemical computations, performed at the MP2, the CCSD(T), and occasionally the CCSDTQ levels employing extended basis sets. Both the experiments and the computations are consistent with structures for the species with n = 3 and 6 being of T-shaped C2 and of D4 symmetry, respectively, while the species with n = 4 are suggested to exhibit interesting dynamical phenomena related to large-amplitude motions.
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