Threshold ionization, structural isomers, and electronic states of M 2O2 (M = Sc, Y, and La)

Lu Wu, Changhua Zhang, Serge A. Krasnokutski, Dong Sheng Yang

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12 Scopus citations


M2O2 (M = Sc, Y, and La) were synthesized in a pulsed laser-vaporization molecular beam source and studied by mass-analyzed threshold ionization (MATI) spectroscopy and ab initio calculations. Adiabatic ionization energies (AIEs) and several vibrational frequencies were measured accurately for the first time from the MATI spectra. Six possible structural isomers of M2O2 were considered in the calculations and the three converged structures were used in the spectral analysis. A planar cyclic structure in D2h point group was predicted to be the most stable one by the theory and observed by the experiment. The cyclic structure is formed by joining two MO2 fragments together through two shared oxygen atoms. In forming the ground state clusters, each metal atom loses two (n - 1)d electrons and as a result, has only one ns electron in the metal-based valence orbital. The ground electronic state of Sc2O2 is 1Ag, and those of Y2O2 and La 2O2 are 3B1u. Ionization of both 1Ag and 3B1u neutral states yields the 2Ag ion state by removing one of the two ns electrons, and the resultant ion has a similar geometry to the neutral cluster. The AIEs of the clusters are 5.5752 (6), 5.2639 (6), 4.5795 (6) eV for M = Sc, Y, and La, respectively. The vibrational frequencies of the observed modes, including O-M and M-M stretches, are in the range of 200-800 cm-1.

Original languageEnglish
Article number224307
JournalJournal of Chemical Physics
Issue number22
StatePublished - Jun 14 2014

ASJC Scopus subject areas

  • General Physics and Astronomy
  • Physical and Theoretical Chemistry


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