Ab Initio Assignments of FIR, MIR, and Raman Bands of Bulk Ba Species Relevant in NOx Storage-Reduction

Vibrational characteristics of bulk Ba species relevant in NOx storage and reduction, namely, BaO, BaO2, Ba(NO3)(2), and BaCO3, have been investigated by first-principle calculations and compared with experimental Far-IR, Mid-IR, and Raman spectra. IR and Raman intensities were calculated and compared to experimental data reported in literature. The study provides an unambiguous and firm assignment of experimentally observed bands for these important barium compounds and a detailed description of the corresponding vibrational modes.