title: Ionic bonding in free nanoscale NaCl clusters as seen by photoelectron spectroscopy.
abstract: The free neutral nanoscale NaCl clusters have been produced in a beam and studied with x-ray photoelectron spectroscopy. High resolution spectra simultaneously containing cluster and molecular-monomer, featuring in both the valence and core-level Na 2p and Cl 2p regions, have been obtained. Cluster-level energy shifts of around 3 eV toward lower binding energy for Na 2p and ≈1 eV toward higher binding energy for Cl 2p relative to the monomer levels have been unambiguously established. To rationalize the core-level energy shifts of the nanoscale NaCl clusters, the ionic model taking into account all charge-charge and polarization interactions has been developed and implemented. A satisfactory agreement between the experimental and model results has been obtained. The model calculations have also shed additional light on the size- and site-specific cluster responses.
authors: Department of Physics and Astronomy, Box 516, 751 20 Uppsala, Sweden.
authors: Chaofan
authors: C
authors: Zhang
authors: Tomas
authors: T
authors: Andersson
authors: Svante
authors: S
authors: Svensson
authors: Olle
authors: O
authors: Björneholm
authors: Marko
authors: M
authors: Huttula
authors: Mikko-Heikki
authors: MH
authors: Mikkelä
authors: Maxim
authors: M
authors: Tchaplyguine
authors: Gunnar
authors: G
authors: Öhrwall