Nitrogen matrix reactions of alkaline earth metal atoms with ozone: Infrared spectra of the alkaline earth metal oxide molecules

The infrared spectra of the alkaline earth metal−ozone−nitrogen reaction mixtures were obtained, and the frequencies of the alkaline earth metal oxide molecules were measured in nitrogen matrices. These were found to be 613, 620, and 707 cm−1 for BaO, SrO, and CaO, respectively; these assignments were confirmed by oxygen−18 substitution. From the known gas phase fundamentals and 1Σ ground electronic states of SrO and BaO, and the anticipated matrix shifts, the ground state of CaO was determined to be 1Σ owing to near agreement between the known 1Σ CaO gas phase fundamental and the CaO nitrogen matrix frequency. Ozone was found to be an excellent precursor for oxygen atom abstraction reactions in nitrogen matrices, while nitrous oxide was considerably less productive. The pattern of reactivity of the alkaline earth metals was determined to be decreasing from barium to magnesium, in agreement with earlier researchers and the work presented in the preceding paper in this series.