title: Rydberg states of small NaAr(n)* clusters.
abstract: The 4s and 5s Rydberg excited states of NaAr(n)* clusters are investigated using a pseudopotential quantum-classical method. While NaAr(n) clusters in their ground state are known to be weakly bound van der Waals complexes with Na lying at the surface of the argon cluster, isomers in 4s or 5s electronically excited states of small NaAr(n)* clusters (n< or =10) are found to be stable versus dissociation. The relationship between electronic excitation and cluster geometry is analyzed as a function of cluster size. For both 4s and 5s states, the stable exciplex isomers essentially appear as sodium-centered structures with similar topologies, converging towards those of the related NaAr(n)+ positive ions when the excitation level is increased. This is consistent with a Rydberg-type picture for the electronically excited cluster, described by a central sodium ion solvated by an argon shell, and an outer diffuse electron orbiting around this NaAr(n)+ cluster core.
authors.affiliation: Laboratoire d'Etudes des Milieux Ionisés et Réactifs (EMIR), Institut Préparatoire aux Etudes d'Ingénieurs, 5019 Monastir, Tunisia.
authors.forename: M Ben
authors.initials: MB
authors.lastname: El Hadj Rhouma
authors.forename: Z
authors.initials: Z
authors.lastname: Ben Lakhdar
authors.forename: H
authors.initials: H
authors.lastname: Berriche
authors.forename: F
authors.initials: F
authors.lastname: Spiegelman