[Show abstract][Hide abstract] ABSTRACT: We investigate the interatomic Coulombic decay (ICD) of neon dimers following photoionization with simultaneous excitation of the ionized atom (shakeup) in a multiparticle coincidence experiment. We find that, depending on the parity of the excited state, which determines whether ICD takes place via virtual dipole photon emission or overlap of the wave functions, the decay happens at different internuclear distances, illustrating that nuclear dynamics heavily influence the electronic decay in the neon dimer.
[Show abstract][Hide abstract] ABSTRACT: We report on molecular frame angular distributions of 2s photoelectrons and electrons emitted by interatomic Coulombic decay from neon dimers. We found that the measured angular distribution of the photoelectron strongly depends on the environment of the cluster. The experimental results are in excellent agreement with frozen core Hartree–Fock calculations. The ICD electrons show slight variations in their angular distribution for different kinetic energies.
Journal of Physics B Atomic Molecular and Optical Physics 06/2007; 40(13):2597. · 1.92 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The regular periodic intensity bursts recently observed in the expansion of solid 4He into vacuum have anomalies that have been attributed to a transition to some new solid phase induced by excess vacancies.
Here it is shown that a small concentration of 3He, from 1% down to 0.1%, added to the 4He solid is sufficient to remove all the anomalies. The origin of the observed anomalies is discussed in the light of these
Journal of Low Temperature Physics 02/2007; 146(3):393-402. · 1.04 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The particle flux through a micron-sized orifice into vacuum from a source chamber filled with solid 4He exhibits a striking sequence of periodic bursts. The period increases (decreases) with pressure (temperature), vanishing at the melting point for temperatures above the upper lambda point at 1.76 K. The oscillations are attributed to a periodic collapse of the solid induced by the accumulation of excess vacancies injected at the orifice and the period provides information on vacancy diffusivity. Dramatic deviations from this behavior below 1.76 K suggest important modifications in the flow properties of solid 4He induced by the excess vacancies.
[Show abstract][Hide abstract] ABSTRACT: Recently Cederbaum et al. [Phys. Rev. Lett. 79, 4778 (1997)]] predicted a new decay channel of excited atoms and molecules termed interatomic Coulombic decay (ICD). In ICD the deexcitation energy is transferred via virtual photon exchange to a neighboring atom, which releases it by electron emission. We report on an experimental observation of ICD in 2s ionized neon dimers. The process is unambiguously identified by detecting the energy of two Ne1+ fragments and the ICD electron in coincidence, yielding a clean, background free experimental spectral distribution of the ICD electrons.
[Show abstract][Hide abstract] ABSTRACT: The particle flux through a two micron diameter orifice into vacuum from a source chamber filled with solid He exhibits a striking periodic behavior similar to that of a geyser. This phenomenon is attributed to a periodic collapse of the solid inside the source induced by the accumulation of excess vacancies injected at the orifice. The flux-time curves agree well with a kinetic model and provide direct information on the diffusivity of vacancies in solid He.