Studies of the chromium oxygenated cluster ions produced during the laser ablation of chromium oxides by laser ablation/ionization Fourier transform ion cyclotron resonance mass spectrometry

Abstract

Trivalent and hexavalent chromium oxides have been examined by time-of-flight laser microprobe mass spectrometry and Fourier transform ion cyclotron resonance mass spectrometry (FTICRMS). The positive-ion spectra show a strong correlation with the valency of chromium in the oxide. Thus, the positive cluster ion distribution and the presence of characteristic chromium cluster ions allow us to distinguish the two oxides. Because of their important role in the formation of large chromium cluster ions, we have investigated the formation mechanism of precursor ions such as CrO+. In this context, FTICRMS has been used to detect the presence of singlet oxygen 1O2(1Δg) and to show its importance in the clustering process. Finally, our hypothesis concerning CrO+ formation involving the Cr+ ion and singlet oxygen 1O2(1Δg) was confirmed. © 1997 John Wiley & Sons, Ltd.