Optical Spectra of Matrix‐Isolated Aluminium

A reinvestigation of matrix‐isolated aluminium shows that the optical spectra of previously published work on Al contained prominent bands originating from Al 2 O. We report for the first time the absorption and emission yield spectra of Al atoms in noble gas matrices which are free of aluminium suboxide contamination. A study of the concentration dependence allowed a decision as to which bands in the spectral range from 450 nm to 200 nm belong to Al, Al 2 and Al 2 O. From the vibronic fine structure of an absorption band at 3 eV for Al 2 , ω e = 238 ± 5 cm −1 is found for the dimer in Ar, Kr and Xe. For Al atoms in Kr two rather stable trapping sites are observed.