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The Optical Spectrum of Au 2 +
Author(s) -
Förstel Marko,
Pollow Kai Mario,
Saroukh Karim,
Najib Este Ainun,
Mitric Roland,
Dopfer Otto
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202011337
Subject(s) - diatomic molecule , multireference configuration interaction , atomic physics , chemistry , photodissociation , electronic structure , spectroscopy , spin (aerodynamics) , ion , spin–orbit interaction , spectral line , coupling (piping) , vibronic coupling , molecular physics , physics , configuration interaction , excited state , computational chemistry , molecule , materials science , quantum mechanics , photochemistry , organic chemistry , thermodynamics , metallurgy
The electronic structure of the Au 2 + cation is essential for understanding its catalytic activity. We present the optical spectrum of mass‐selected Au 2 + measured via photodissociation spectroscopy. Two vibrationally resolved band systems are observed in the 290–450 nm range (at ca. 440 and ca. 325 nm), which both exhibit rather irregular structure indicative of strong vibronic and spin‐orbit coupling. The experimental spectra are compared to high‐level quantum‐chemical calculations at the CASSCF‐MRCI level including spin‐orbit coupling. The results demonstrate that the understanding of the electronic structure of this simple, seemingly H 2 + ‐like diatomic molecular ion strictly requires multireference and relativistic treatment including spin‐orbit effects. The calculations reveal that multiple electronic states contribute to each respective band system. It is shown that popular DFT methods completely fail to describe the complex vibronic pattern of this fundamental diatomic cation.