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The resonant-Auger - interatomic Coulombic decay (ICD) cascade was recently suggested as an efficient means of controlling the course of the ICD process. Recent theoretical and experimental works show that control over the energies of the emitted ICD electrons can be achieved either by varying the photon energy to produce different initial core excitations or by changing the neighboring species. This work presents a theoretical investigation on the role of the rare-gas neighbor and clarifies how the latter influences the ICD process. For this purpose, we compare fully ab initio computed ICD-electron and kinetic energy release spectra following the 2p3/2 → 4s, 2p 1/2 → 4s and 2p3/2 → 3d of Ar in ArKr and Ar2. We demonstrate that the presence of the chemically "softer" partner atom results in an increase in the energies of the emitted ICD electrons, and also in the appearance of additional ICD-active states. The latter leads to a threefold increase in the ICD yield for the case of the 2p3/2,1/2 → 4s parent core excitations. [ABSTRACT FROM AUTHOR]

A scheme utilizing excitation of core electrons followed by the resonant-Auger - interatomic Coulombic decay (RA-ICD) cascade was recently proposed as a means of controlling the generation site and energies of slow ICD electrons. This control mechanism was verified in a series of experiments in rare gas dimers. In this article, we present fully ab initio computed ICD electron and kinetic energy release spectra produced following 2p3/2 → 4s, 2p1/2 → 4s, and 2p3/2 → 3d core excitations of Ar in Ar2. We demonstrate that the manifold of ICD states populated in the resonant Auger process comprises two groups. One consists of lower energy ionization satellites characterized by fast interatomic decay, while the other consists of slow decaying higher energy ionization satellites. We show that accurate description of nuclear dynamics in the latter ICD states is crucial for obtaining theoretical electron and kinetic energy release spectra in good agreement with the experiment. [ABSTRACT FROM AUTHOR]

Excitation of HeNe by synchrotron light just below the frequency of the 1s→3p transition of isolated He has been recently shown to be followed by resonant interatomic Coulombic decay (ICD). The vibrationally resolved widths of the ICD states were extracted with high precision from the photoion spectra. In this paper, we report the results of ab initio calculations of these widths. We show that interaction between electronic states at about the equilibrium distance of HeNe makes dark states of He accessible for the photoexcitation and subsequent electronic decay.Moreover, the values of the calculated widths are shown to be strongly sensitive to the presence of the non-adiabatic coupling between the electronic states participating in the decay. Therefore, only by considering the complete manifold of interacting decaying electronic states a good agreement between the measured and computed ICD widths can be achieved. [ABSTRACT FROM AUTHOR]

We analyze in detail the accessible relaxation pathways via electron emission of the Ne2+Ar states populated via the K-LL Auger decay of Ne+(1s-1)Ar. In particular, we concentrate on the “direct” interatomic Coulombic decay (ICD) of the Ne2+(2s-12p-1)Ar weakly bound doubly ionized states into the manifold of the Ne2+(2p-2)–Ar+(3p-1) repulsive triply ionized ones. To carry out the present study the potential energy curves of the NeAr ground state, the core ionized state Ne+(1s-1)Ar, the relevant dicationic and tricationic states, and the corresponding ICD transition rates have been computed using accurate ab initio methods and basis sets. The total and partial ICD electron spectra are computed within the framework of the time-dependent theory of wave packet propagation. Thereby, the impact of nuclear dynamics accompanying the electronic decay on the computed ICD-electron spectra is investigated in detail. [ABSTRACT FROM AUTHOR]

In this paper we study the impact of interatomic Coulombic decay (ICD) on molecular photodissociation. The investigation reveals the hitherto unrecognized ability of ICD to quench processes involving nuclear rearrangements. Numerical computations of the nuclear dynamics, initiated by photoexciting the B1Σ+ Rydberg state of CO in CO·Mg complexes, are carried out. The efficiencies of ICD and photoinduced predissociation are compared for the four lowest vibrational levels of the corresponding electronic state. We also show the impact of CO vibrations on the ICD electron spectrum. Finally, we discuss the growing efficiency of ICD to quench the dissociation as the number of neighboring Mg atoms is increased. [ABSTRACT FROM AUTHOR]