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On the Photoabsorption by Permanganate Ions in Vacuo and the Role of a Single Water Molecule. New Experimental Benchmarks for Electronic Structure Theory
Author(s) -
Houmøller Jørgen,
Kaufman Sydney H.,
Støchkel Kristian,
Tribedi Lokesh C.,
Brøndsted Nielsen Steen,
Weber J. Mathias
Publication year - 2013
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201300019
Subject(s) - electronic structure , absorption spectroscopy , molecule , chemistry , blueshift , photodissociation , spectroscopy , ion , aqueous solution , permanganate , spectral line , photochemistry , absorption (acoustics) , density functional theory , chemical physics , materials science , computational chemistry , physics , optics , optoelectronics , organic chemistry , quantum mechanics , astronomy , composite material , photoluminescence
We report electronic spectra of mass‐selected MnO 4 − and MnO 4 − ⋅H 2 O using electronic photodissociation spectroscopy. Bare MnO 4 − fragments by formation of MnO 3 − and MnO 2 − , while the hydrated complex predominantly decays by loss of the water molecule. The band in the visible spectral region shows a well‐resolved vibrational progression consistent with the excitation of a MnO stretching mode. The presence of a single water molecule does not significantly perturb the spectrum of MnO 4 − . Comparison with the UV/Vis absorption spectrum of permanganate in aqueous solution shows that complete hydration causes a small blueshift, while theoretical models including a dielectric medium have predicted a redshift. The experimental data can be used as benchmarks for electronic structure theory methods, which usually predict electronic spectra in the absence of a chemical environment.