ESR and Optical Spectroscopy of the AlO Molecule at 4 K; Observation of an Al Complex and Its Interaction with Krypton
Knight, L. B. ESR and Optical Spectroscopy of the AlO Molecule at 4 K; Observation of an Al Complex and Its Interaction with Krypton. J. Chem. Phys. 1971, 55, 5066-5066.
The AlO molecule in its 2Î£ ground state has been trapped in neon, argon, and krypton matrices at 4Â°K, and its ESR and optical spectra (infrared, visible, and uv) measured. In neon its magnetic parameters are g â€– = 2.0015(3),â€‰g âŠ¥ = 2.0004(3),â€‰A â€– ( 27 Al ) = 872(1) MHz , and A âŠ¥ ( 27 Al ) = 713(1) MHz . Î” gâŠ¥ is in accord with the magnitude and sign of the spinâ€doubling constant, Î³0, determined in the gas phase. An infrared band at 924 cmâˆ’1 in neon (917 cmâˆ’1 in argon) is assigned to AlO: the large shift from the gas value of 965 cmâˆ’1 indicates a highly ionic molecule. Besides the strong B 2Î£â†X 2Î£ absorption bands near 4500 Ã…, a progression of weak bands have been observed between 5500 and 11 000 cmâˆ’1 and assigned to the A 2Ï€ i â†X 2Î£ transition of AlO. ESRspectra of a weakly bonded Al â€“ X molecule (where X may be Al2O) are observed in concentrated matrices; its magnetic properties are found to be very dependent upon the matrix gas used. In krypton matrices, 83Kr hfs is also observed but disappears (reversibly) above about 35Â°K, suggesting the formation of a metastable Kr â€“ AlX complex.
Journal of Chemical Physics