Infrared spectra and structure of some matrix-isolated lanthanide and actinide oxides

Abstract

The midinfrared spectra of the oxides of Ce, Pr, Sm, Eu, Tb, and Th have been obtained by vaporizing the solid oxides and trapping the vapor species in argon matrices. On the basis of oxygen-18 isotope shifts, a linear structure has been determined for PrO2, and nonlinear structures for CeO2, TbO2, and ThO2. Values of ωe and ωeχe have been determined for the monoxides of Pr, Eu, Tb, and Th from the small deviations between the observed and the theoretical harmonic isotope shifts.

A Critical Appraisal of the Experimental Data on the Molecular Structure and Spectra of Halides, Oxides, and Hydrides of the s-, d-, and f-Block Elements

“…Both CeO 2 28 and 121 AE 28). [100] Although the angle for CeO 2 (isoelectronic with BaF 2 ) is large and the assignments of two IR bands reverse those in an earlier paper, [101] the authors present a consistent argument for nonlinearity. Praseodymium dioxide, which has a central atom with a partially filled f shell, is a linear molecule.…”

“…Praseodymium dioxide, which has a central atom with a partially filled f shell, is a linear molecule. [100] In the case of the actinides ThO 2 (d 0 f 0 ) is nonlinear (122.5 AE 28), [100] while UO 2 [102] and PuO 2 [103] both have partially filled shells and are linear. This work on the lanthanides and actinides is mainly from the group at Argonne National Laboratory, and the IR spectra are of high quality.…”

Synthesis and Structures of Plutonyl Nitrate Complexes: Is Plutonium Heptavalent in PuO3(NO3)2– ?

“…2 In the case of Pu(VII) in the gas phase, it has been predicted that PuO 3 1 which is only ca. 0.6 V higher than the Ce(IV/III) reduction potential; CeO 2 is a stable molecule 11 and it might be feasible to oxidize Pu(VI) to Pu(VII) in the gas phase. An important caveat in this evaluation is that the reported Pu(VII) reduction potential is for highly basic conditions such that direct comparison of these values is not necessarily indicative of comparative intrinsic stabilities of the oxidation states.…”

Structures and vibrational spectroscopy of partially reduced gas-phase cerium oxide clusters

“…Since DFT calculations are of limited accuracy the final structure assignment is achieved by comparing the infrared (IR) absorption spectra, calculated for the lowest energy isomers, with measured IR vibrational predissociation 12 (IRVPD) spectra. Previously, this approach was applied to determine the structures of other metal oxide cluster cations, including vanadium, 13 [16][17][18][19][20][21][22][23][24][25][26][27][28][29] there are two novel aspects within our study. First, the structures are computationally predicted using ab initio global structure optimizations.…”

“…So far IR matrix isolation 16,17 and visible fluorescence 18,19 spectroscopy have been used to characterize CeO and CeO 2 .…”