title: Study of cluster anions generated by laser ablation of titanium oxides: a high resolution approach based on Fourier transform ion cyclotron resonance mass spectrometry.
abstract: Laser ablation of titanium oxides at 355 nm and ion-molecule reactions between [(TiO(2))(x)](-•) cluster anions and H(2)O or O(2) were investigated by Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) with an external ion source. The detected anions correspond to [(TiO(2))(x)(H(2)O)(y)OH](-) and [(TiO(2))(x)(H(2)O)(y)O(2)](-•) oxy-hydroxide species with x=1 to 25 and y=1, 2, or 3 and were formed by a two step process: (1) laser ablation, which leads to the formation of [(TiO(2))(x)](-•) cluster anions as was previously reported, and (2) ion-molecule reactions during ion storage. Reactions of some [(TiO(2))(x)](-•) cluster anions with water and dioxygen conducted in the FTICR cell confirm this assessment. Tandem mass spectrometry experiments were also performed in sustained off-resonance irradiation collision-induced dissociation (SORI-CID) mode. Three fragmentation pathways were observed: (1) elimination of water molecules, (2) O(2) loss for radical anions, and (3) fission of the cluster. Density functional theory (DFT) calculations were performed to explain the experimental data.
authors.affiliation: Laboratoire de Spectrométrie de Masse et de Chimie Laser, Institut Jean Barriol Fédération de Recherche 2843, Université Paul Verlaine-Metz 1, Boulevard Arago Metz Technopôle, F-57078 Cedex 03, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Barthen
authors.forename: Eric
authors.initials: E
authors.lastname: Millon
authors.forename: Frédéric
authors.initials: F
authors.lastname: Aubriet