Experimental Evidence for Interatomic Coulombic Decay in Ne Clusters

Electron spectra of photoexcited Ne clusters are shown to display a signal at low kinetic energies that is neither present in the Ne monomer nor at photon energies below the inner-valence 2s threshold. These findings are strong evidence for the existence of interatomic Coulombic decays (ICD), a mechanism that was recently predicted theoretically [<article>Phys. Rev. Lett.<coden>PRLTAO</coden><issn>0031-9007</issn> 79, 4778 (1997)</article>]. In ICD, an inner-valence hole state in a weakly bonded system can undergo ultrafast relaxation due to energy transfer to a neighboring atom, followed by electron emission from this neighboring site.