MAGNETIC CIRCULAR AND LINEAR DICHROISM SATURATION STUDIES - DETERMINATION OF THE CRYSTAL-FIELD SPLITTING IN KRYPTON AND XENON MATRIX-ISOLATED IRON ATOMS

The site symmetry and magnitude of the crystal field splitting of meta l atoms trapped in rare gas matrices may be determined by a combinatio n of the temperature and magnetic field dependence of magnetic circula r dichroism (MCD) and magnetic linear dichroism (MLD). General theoret ical expressions are derived for the MCD and MLD considering the Zeema n effect and the matrix (i.e., crystal field) as perturbations on the free atom \JM(J)] states. These expressions are applied to the observe d MCD and MLD T- and B-saturation curves for Fe atoms isolated in kryp ton and xenon matrices in the range 0-1.5 T and 2.3-22 K. An octahedra l crystal field model accounts well for all four independent sets of d ata (MCD vs B, MCD vs 1/T, MLD vs B-2, and MLD vs 1/T-2) for two diffe rent, isolated electronic transitions. A crystal field parameter of +0 .06+/-0.05 cm(-1) has been determined, corresponding to an overall ele ctronic ground-state splitting of 3.2+/-2.5 cm(-1). This splitting is less than the optical bandwidth and is shown to be consistent with pre vious studies of rare gas matrix-isolated Fe atoms by Mossbauer and la ser-excited emission spectroscopies.