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Updated: Jan 28, 2026

Determination of the Gas-phase Acidities of Oligopeptides
Published on: June 24, 2013
Action-spectroscopy studies of positively charge-tagged azobenzene in solution and in the gas-phase
Elisabeth Gruber1, Marcel A Strauss2, Hermann A Wegner2
1Department of Physics and Astronomy, Aarhus University, 8000 Aarhus, Denmark.
Abstract:
The absorption of a positively charge-tagged azobenzene molecule is studied in the gas-phase by measuring photoinduced fragmentation of ions as a function of time. This technique provides information on prompt as well as delayed fragmentation, and a single dissociation channel after one-photon absorption is identified. The spectra in solution, as well as in the gas-phase, show a weak S0 → S1, a strong S0 → S2, and a broad absorption band in the UV regime. The bands are assigned through time dependent density functional theory calculations. The ratio of the various absorption bands depends on the trans to cis isomerization fraction and may be tuned by light irradiation. Gas-phase absorption spectra are presented and discussed in terms of trans and cis isomers.
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