Electron Diffraction Self-Imaging of Molecular Fragmentation in Two-Step Double Ionization of Water

Institut für Kernphysik, J. W. Goethe Universität, Max-von-Laue-Str. 1, 60438 Frankfurt, Germany.
Physical Review Letters (Impact Factor: 7.51). 04/2011; 106(13):133001. DOI: 10.1103/PhysRevLett.106.133001
Source: PubMed


We doubly ionize H(2)O by single photon absorption at 43 eV leading to H(+) + OH(+). A direct double ionization and a sequential process in which single ionization is followed by rapid dissociation into a proton and an autoionizing OH(*) are identified. The angular distribution of this delayed autoionization electron shows a preferred emission in the direction of the emitted proton. From this diffraction feature we obtain internuclear distances of 700 to 1100 a.u. at which the autoionization of the OH(*) occurs. The experimental findings are in line with calculations of the excited potential energy surfaces and their lifetimes.

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