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Formation and decay of the dehydrogenated parent anion upon electron attachment to dialanine
David Gschliesser1, Violaine Vizcaino, Michael Probst
1Institut für Ionenphysik und Angewandte Physik and Center for Molecular Biosciences Innsbruck, Leopold-Franzens-Universität Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria.
Abstract:
The dehydrogenated parent anion [M-H](-) is one of the most dominant anions formed in dissociative electron attachment to various small biomolecules like nucleobases and single amino acids. In the present study, we investigate the [M-H](-) channel for the dipeptide dialanine by utilizing an electron monochromator and a two-sector-field mass spectrometer. At electron energies below 2 eV, the measured high-resolution ion-efficiency curve has a different shape to that for the single amino acid alanine, which is explained by the altered threshold energies for formation of [M-H](-) determined in quantum chemical calculations. Moreover, the structure of the formed [M-H](-) anion is further studied by investigating the unimolecular and collision-induced decay of this anion. Trajectory calculations have been carried out to aid the interpretation of the experimentally observed fragmentation patterns.
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