Characterization of the Reaction Products of Laser-Ablated Early Lanthanide Metal Atoms with Molecular Oxygen. Infrared Spectra of LnO, LnO+, LnO-, LnO2, LnO2+, LnO2-, LnO3-, and (LnO)2 in Solid Argon

This paper is the first of a two-part study of the reaction products of laser-ablated lanthanide metal atoms with O 2 . There is general agreement with previous gas-phase and matrix-isolated neutral monoxides of the lanthanide elements. The present results agree with earlier identifications of CeO 2 and PrO 2 and make new assignments for NdO 2, SmO 2, EuO 2, and GdO 2 . In addition, this work provides vibrational frequencies for six LnO +, five LnO -, two LnO 2 +, six LnO 2 -, and two LnO 3 - species; five (LnO) 2 rings are also reported here for the first time. Low ionization energies for the metals and the LnO molecules facilitate production of the LnO + cations and make electrons available for capture to form molecular anions. The doping of CCl 4 into these samples provides a diagnostic test for the identification of molecular cations and anions by matrix infrared spectroscopy.