Formation, stability, and structures of antimony oxide cluster ions

An ab initio study on the ground and low-lying doublet electronic states of SbO2

Geometry optimization and harmonic vibrational frequency calculations have been carried out on the low-lying doublet electronic states of antimony dioxide (SbO(2)) employing a variety of ab initio methods, including the complete active space self-consistent field/multireference configuration interaction and the RCCSD(T) methods. Both large and small core relativistic effective core potentials were used for Sb in these calculations, together with valence basis sets of up to aug-cc-pV5Z quality. Contributions from outer core correlation and off-diagonal spin-orbit interaction to relative electronic energies have been calculated. The ground electronic state of SbO(2) is determined to be the X (2)A(1) state, as is the case for dioxides of other lighter group 15 p-block (or group VA) elements. However, the A (2)B(2) and B (2)A(2) states are estimated to be only 4.1 and 10.7 kcalmole above the X (2)A(1) state, respectively, at the complete basis set limit. Reliable vertical excitation energies from the X (2)A(1) state to low-lying excited states of SbO(2) have been computed with a view to assist future spectral assignments of the absorption and/or laser-induced fluorescence spectra of SbO(2), when they become available.

Laser ablation and secondary ion mass spectrometry of inorganic transition-metal compounds. Part I: comparison between static ToF-SIMS and LA-FTICRMS

Most of the first-row transition-metal oxides, M(A)O(B) (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn) were examined by static secondary ion mass spectrometry (s-SIMS) and laser ablation/ionization Fourier transform ion cyclotron resonance mass spectrometry (LA-FTICRMS). Positive and negative ions show strong correlation between the studied oxide and the detected cluster ions. Specific M(x)O(y) (+/-) species were systematically observed with both MS techniques for each investigated M(A)O(B) transition-metal oxide. Moreover, the ion composition and ion distribution are greatly dependent on the ionization technique. Laser ablation (LA)/ionization leads to larger cluster ions (ionic species with nearly hundred atoms were in particular detected for Sc2O3 and Y2O3 oxides), whereas hydrogenated, dihydrogenated, and sometimes trihydrogenated species were observed in s-SIMS. However, the ion distribution for a given M(x)O(y) (+/-) ion series (i.e. ions including the same number of metal atoms M) generally presented important similarities in both techniques.Finally, it was demonstrated that the chemical state of metal atoms in the observed ionic species is closely dependent on the metal electronic valence shell. High valence states (+III, +IV, +V, and +VI) are favored for metals with a less-than-half full valence shell configuration, whereas for other first-row transition metals (manganese, iron, cobalt, nickel, copper and zinc) lower metal valence states (0, +I or, +II) are involved.