Self-assembled heterogeneous argon/neon core-shell clusters studied by photoelectron spectroscopy

Abstract

Clusters formed by a coexpansion process of argon and neon have been studied using synchrotron radiation. Electrons from interatomic Coulombic decay as well as ultraviolet and x-ray photoelectron spectroscopy were used to determine the heterogeneous nature of the clusters and the cluster structure. Binary clusters of argon and neon produced by coexpansion are shown to exhibit a core-shell structure placing argon in the core and neon in the outer shells. Furthermore, the authors show that 2 ML of neon on the argon core is sufficient for neon valence band formation resembling the neon solid. For 1 ML of neon the authors observe a bandwidth narrowing to about half of the bulk value.

Interatomic Coulombic decay in mixed NeKr clusters

“…We have demonstrated the occurrence of Interatomic Coulombic Decay (ICD) in the decay of Ne 2s −1 ionic states, similar to earlier findings in heterogeneous weakly bound rare gas clusters. 20,21 The ICD feature has an unusually high kinetic energy of about 10 eV, thus separating it more clearly in energy from the secondary electrons and making the system a potential candidate for further spectroscopic characterization. Further, the results show that the ICD feature shifts towards higher kinetic energies, on increasing the amount of Kr in the gas mixture, but not on increasing the cluster size at the same mixing ratio.…”

Charge and energy transfer in argon-core–neon-shell clusters irradiated by free-electron-laser pulses at 62 nm

“…In addition, TOF-MS and KED were measured for clusters ( N = 1000) produced from 3% Ar and enriched 22 Ne premixed gas by using weak (∼10 11 W/cm 2 ) FEL pulses with λ = 51 nm (i.e., 2.4 eV above the Ne ionization potential of 21.6 eV) to determine the Ar content within the clusters.…”

“…Before drawing conclusions, one should examine Ar enrichment effects in the core [22]. For this purpose, the Ar enrichment factor for 3% Ar-Ne was directly determined: We produced Ar-core-Ne-shell clusters ( N = 1000) from 3% Ar and enriched (more than 99%) 22 Ne premixed gas, and measured TOF-MS and KED with 24.3 eV FEL pulses, which ionize not only Ar but also Ne atoms by one-photon absorption.…”

“…For this purpose, the Ar enrichment factor for 3% Ar-Ne was directly determined: We produced Ar-core-Ne-shell clusters ( N = 1000) from 3% Ar and enriched (more than 99%) 22 Ne premixed gas, and measured TOF-MS and KED with 24.3 eV FEL pulses, which ionize not only Ar but also Ne atoms by one-photon absorption. Nonlinear optical phenomena were avoided by keeping the FEL intensity weak (∼10 11 W/cm 2 ).…”

“…In this paper, we adopted Ar-Ne mixed clusters which are known to be self-assembled to a core-shell structure [22]. We present experimental studies on pristine Ne clusters and heterogeneous Ar-core-Ne-shell clusters irradiated by intense 62 nm (20 eV) pulses from the free-electron laser.…”