title: The Electronic Structure of the Al3(-) Anion: Is it Aromatic?
abstract: Multiconfigurational high-level electronic structure calculations show that the Al3(-) ring-like cluster anion has three close low-lying electronic states of different spin, all of them having strong multiconfigurational character. The aromaticity of the cluster has, therefore, been studied by means of total electron delocalization and normalized multicenter electron delocalization indices evaluated from the multiconfigurational wave functions of each state. The lowest-lying singlet and triplet states are found to be highly aromatic, whereas the next lowest-lying state, the quintet state, has much less, though non-negligible, aromatic character.
authors.affiliation: IZO-SGI SGiker, Euskal Herriko Unibertsitatea (UPV/EHU) (Spain). jm.mercero@ehu.eus.
authors.forename: Jose M
authors.initials: JM
authors.lastname: Mercero
authors.affiliation: IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Euskadi (Spain).|Kimika Fakultatea, Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International Physics Center (DIPC), P.K. 1072, 20080 Donostia, Euskadi (Spain).
authors.forename: Eduard
authors.initials: E
authors.lastname: Matito
authors.affiliation: POLYMAT, University of the Basque Country UPV/EHU, Joxe Mari Korta Center, Avda. Tolosa 72, 20018 Donostia, Euskadi (Spain).
authors.forename: Fernando
authors.initials: F
authors.lastname: Ruipérez
authors.affiliation: Faculty of Sciences, Department of Theoretical Chemistry, Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV, Amsterdam (The Netherlands).|Kimika Fakultatea, Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International Physics Center (DIPC), P.K. 1072, 20080 Donostia, Euskadi (Spain).
authors.forename: Ivan
authors.initials: I
authors.lastname: Infante
authors.affiliation: Kimika Fakultatea, Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International Physics Center (DIPC), P.K. 1072, 20080 Donostia, Euskadi (Spain).
authors.forename: Xabier
authors.initials: X
authors.lastname: Lopez
authors.affiliation: Kimika Fakultatea, Euskal Herriko Unibertsitatea (UPV/EHU) and Donostia International Physics Center (DIPC), P.K. 1072, 20080 Donostia, Euskadi (Spain).
authors.forename: Jesus M
authors.initials: JM
authors.lastname: Ugalde
keywords: all-metal aromaticity; aluminum; high-level ab initio calculations; multiconfiguational