Formation of iron oxides clusters induced by resonant laser ablation/ionization

✍ Scribed by B. Maunit; A. Hachimi; P. Manuelli; P.J. Calba; J.F. Muller

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 873 KB
• Volume: 156
• Category: Article
• ISSN: 0168-1176
• DOI: 10.1016/s0168-1176(96)04423-0

✦ Synopsis

The present work has been conducted by Time-of-Flight Laser Microprobe Mass Spectrometry (TOF-LMMS) in resonant or non-resonant ionization modes. The targets (micrometric particles of powdered iron oxides Fel_xO, Fe304 and Fe203) were synthesized, on the one hand, from iron 54 isotopes and, on the other hand, from natural iron 56 isotopes. The positive-ion cluster distributions showed a strong correlation with the stoichiometry of iron in oxides. This correlation is even more striking when the resonant ionization process of iron at 278.8 nm is used. The dissociation energy of the Fe-O bond in the Fel_xO bulk also affects the distribution of the intensity of clusters. A better understanding of the way cluster ions (Fe~ and Fe20 ÷ ) are formed will improve our ability to interpret the mass spectra of iron oxides. Indeed, results show that the way Fe~ dimer and Fe2 O+ ions are formed is closely associated with the presence of the neutral species FeO and singlet oxygen IO2 (lAg). Fouriertransform ion cyclotron resonance mass spectrometry (FT/ICR/MS) has been used to detect the presence of oxygen in the singlet 102 (lag) state in the plume generated by laser ablation. The in situ identification of iron oxides in biological samples is very important for studying their role as carriers of certain toxic molecules (e.g. PAH).