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A semiquantitative study of the intermolecular Coulombic decay (ICD) of singly and doubly ionized water dimer has been carried out with the help of ab initio computed ionization spectra and potential energy curves (PECs). These PECs are particular cuts through the (H2O)2, (H2O)2+, and (H2O)2++ hypersurfaces along the distance between the two oxygen atoms. A comparison with the recently published experimental data for the ICD in singly ionized water dimers [T. Jahnke, H. Sann, T. Havermeier et al., Nat. Phys. 6, 139 (2010)] and in large water clusters [M. Mucke, M. Braune, S. Barth et al., Nat. Phys. 6, 143 (2010)] shows that such a simplified description in which the internal degrees of freedom of the water molecules are frozen gives surprisingly useful results. Other possible decay channels of the singly ionized water dimer are also investigated and the influence of the H-atom participating in the hydrogen bond on the spectra of the proton-donor and proton-acceptor molecules in the dimer is discussed. Importantly, the decay processes of one-site dicationic states of water dimer are discussed and an estimate of the ICD-electron spectra is made. More than 33% of the dications produced by Auger decay are found to undergo ICD. The qualitative results show that the ICD following Auger decay in water is also expected to be an additional source of low-energy electrons proven to be extremely important for causing damages to living tissues. [ABSTRACT FROM AUTHOR]

The accessible relaxation channels of the electronic states of Ne++–Ne and Ne3+–Ne populated by KLL Auger decay are studied. In particular, we address the “direct” and “exchange” interatomic Coulombic decays (ICDs) and the electron-transfer-mediated decay following the population of one-site states Ne++(2s-2)–Ne and Ne++(2s-12p-1 1P)–Ne. Radiative charge transfer of the low lying Ne++(2p-2)–Ne states, three-electron ICD process from the Ne++(2s-2)–Ne states, as well as charge transfer at the points of curve crossing of the lowest in energy Ne3+(2p-3)–Ne states are also discussed. To carry out the present study, we have calculated the potential energy curves (from 1.75 to 5.00 Å) of the ground state Ne2, the core ionized state Ne+(1s-1)–Ne, and the dicationic and tricationic states with energies in the range of 45–140 eV using accurate ab initio methods and basis sets. Apart from being of interest by themselves, the results obtained may be helpful in interpreting the recent measurements of interatomic electronic processes following Auger decay in neon dimer [K. Kreidi et al., J. Phys. B 41, 101002 (2008)]. [ABSTRACT FROM AUTHOR]

Potential energy curves of the Auger state Ar+(2p-1)–Ar, the different one- and two-site dicationic states Ar2++ (with energies in the range of 32–77 eV), and the lowest two-site tricationic states Ar++–Ar+ (with energies in the range of 64–76 eV) computed using elaborated ab initio methods are reported. The accessible relaxation channels of the electronic states of Ar++–Ar populated by Auger decay are studied. In particular, we study in detail the interatomic Coulombic decay following the population of one-site satellite states of Ar++(3s-13p-1)–Ar recently observed experimentally. Other relaxation pathways of Ar++–Ar, including radiative charge transfer, nuclear dynamics through curve crossing, and intra-atomic decay processes are also investigated. [ABSTRACT FROM AUTHOR]

Potential energy curves of the Auger state Ar+(2p-1)–Ar, the different one- and two-site dicationic states Ar2++ (with energies in the range of 32–77 eV), and the lowest two-site tricationic states Ar++–Ar+ (with energies in the range of 64–76 eV) computed using elaborated ab initio methods are reported. The accessible relaxation channels of the electronic states of Ar++–Ar populated by Auger decay are studied. In particular, we study in detail the interatomic Coulombic decay following the population of one-site satellite states of Ar++(3s-13p-1)–Ar recently observed experimentally. Other relaxation pathways of Ar++–Ar, including radiative charge transfer, nuclear dynamics through curve crossing, and intra-atomic decay processes are also investigated. [ABSTRACT FROM AUTHOR]