title: Infrared signature of structures associated with the H+(H2O)n (n = 6 to 27) clusters.
abstract: We report the OH stretching vibrational spectra of size-selected H+(H2O)n clusters through the region of the pronounced "magic number" at n = 21 in the cluster distribution. Sharp features are observed in the spectra and assigned to excitation of the dangling OH groups throughout the size range 6 </= n </= 27. A multiplet of such bands appears at small cluster sizes. This pattern simplifies to a doublet at n = 11, with the doublet persisting up to n = 20, but then collapsing to a single line in the n = 21 and n = 22 clusters and reemerging at n = 23. This spectral simplification provides direct evidence that, for the magic number cluster, all the dangling OH groups arise from water molecules in similar binding sites.
authors.affiliation: Sterling Chemistry Laboratory, Yale University, Post Office Box 208107, New Haven, CT 06520, USA.
authors.forename: J-W
authors.initials: JW
authors.lastname: Shin
authors.forename: N I
authors.initials: NI
authors.lastname: Hammer
authors.forename: E G
authors.initials: EG
authors.lastname: Diken
authors.forename: M A
authors.initials: MA
authors.lastname: Johnson
authors.forename: R S
authors.initials: RS
authors.lastname: Walters
authors.forename: T D
authors.initials: TD
authors.lastname: Jaeger
authors.forename: M A
authors.initials: MA
authors.lastname: Duncan
authors.forename: R A
authors.initials: RA
authors.lastname: Christie
authors.forename: K D
authors.initials: KD
authors.lastname: Jordan