title: Photoinduced intermolecular dynamics and subsequent fragmentation in VUV-ionized acetamide clusters.
abstract: Photofragmentation of small gas-phase acetamide clusters (CH3CONH2)n(n ≤ 10) produced by a supersonic expansion source has been studied using time-of-flight ion mass spectroscopy combined with tunable vacuum-ultraviolet (VUV) synchrotron radiation. Fragmentation channels of acetamide clusters under VUV photoionization resulting in protonated and ammoniated clusters formation were identified with the discussion about the preceding intramolecular rearrangements. Acetamide-2,2,2-d3 clusters were also studied in an experiment with a gas discharge lamp as a VUV light source; comparison with the main experiment gave insights into the mechanism of formation of protonated acetamide clusters, indicating that proton transfer from amino group plays a dominant role in that process. Geometry of the acetamide dimer was discussed and the most stable arrangement was concluded to be achieved when subunits of the dimer are connected via two N-H⋯O -C hydrogen bonds. Also, the influence of the photon energy on the stability of the clusters and their fragmentation channels has been examined.
authors: Department of Physics, University of Tartu, EST-50411 Tartu, Estonia.
authors: Marta
authors: M
authors: Tarkanovskaja
authors: Department of Physics, University of Tartu, EST-50411 Tartu, Estonia.
authors: Kuno
authors: K
authors: Kooser
authors: Department of Physics and Astronomy, University of Turku, FIN-20014 Turku, Finland.
authors: Helena
authors: H
authors: Levola
authors: Department of Physics, University of Tartu, EST-50411 Tartu, Estonia.
authors: Ergo
authors: E
authors: Nõmmiste
authors: Department of Physics and Astronomy, University of Turku, FIN-20014 Turku, Finland.
authors: Edwin
authors: E
authors: Kukk