FT-ICR MS studies of ion-molecule reactions of Ru+ and Os+ with oxygen

The reactions of stored ruthenium and osmium cations with oxygen have been studied in a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. In case of osmium the reaction products OsO+ and OsO2+ have been observed and corresponding reaction-rate constants have been determined. In addition, there is an unreactive fraction of Os+ ions due to the presence of a slightly endothermic reacting ground state. Only the excited states react with oxygen. For ruthenium no spontaneous reaction with oxygen has been observed unless the cyclotron motion of Ru+ was excited. The results are discussed with respect to a similar investigation in a Penning trap-TOF mass spectrometer [U. Rieth, A. Herlert, J.V. Kratz, L. Schweikhard, M. Vogel, C. Walther, Radiochim. Acta 90 (2002) 337] and with respect to possible future studies of ion-molecule reactions of the homologous super-heavy element 108 (hassium).