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Title: EPR studies of paramagnetic rhodium centers in LiH and LiD

Journal Article · · J. Chem. Phys.; (United States)
DOI:https://doi.org/10.1063/1.437847· OSTI ID:6335902

EPR spectra have been obtained for two independent paramagnetic Rh centers in UV-irradiated single crystals of LiH and LiD. The spin Hamiltonians for both species indicate S=1/2 and are assigned to Rh/sup 2 +/ ions with low-spin 4d/sup 7/ electron configurations. Analysis of the anisotropic g-factor for the tetragonal center shows the unpaired electron is the Rh 4d/sub x/2-y2 orbital. The unpaired electron occupies the 4d/sub 3z/ /sup 2//sub -r/ /sup 2/ orbital in the orthorhombic center. The g factor, hyperfine constants, and protium superhyperfine constants for the Rh centers in LiH and LiD are compared with similar parameters for Rh/sup 2 +/ ions in several halide and oxide crystals. Although the isotropic protium hyperfine values indicate significant vertical-bar1s>-vertical-bar4d> orbital interactions, the total covalency in the Rh--H(D) bonds is rather small since the hydrogen vertical-bar2p> orbitals cannot participate. The displacements of H ligands in the Rh centers have been determined from the direct-dipolar contributions to the superhyperfine tensor.

Research Organization:
Monsanto Research Corporation, Mound Facility Miamisburg, Ohio 45342
OSTI ID:
6335902
Journal Information:
J. Chem. Phys.; (United States), Vol. 70:6
Country of Publication:
United States
Language:
English