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Characterization of. gamma. -ray induced paramagnetic centers in bayerite by means of EPR and ENDOR spectroscopies

Journal Article · · J. Chem. Phys.; (United States)
OSTI ID:7343453

Four different paramagnetic centers, induced in bayerite samples by irradiation, have been characterized by EPR and ENDOR spectroscopies. Two of them, respectively, of V- and F-types, have been found to be mobile at room temperature and frozen at lower temperature. The first one, with g/sub 1/= 2.021 +- 0.002, g/sub 2/=2.010 +- 0.005, and g/sub 3/=2.005 +- 0.002, is identified with an O/sup -/ species stemming from the ionization of OH/sup -/ groups present in the structural cavity walls of the bayerite. The second one, with g/sub parallel/=1.9970 +- 0.0005 and g/sub perpendicular/=2.0020 +- 0.0005, corresponds to solvated electrons. A third center, with g/sub parallel/=2.035 +- 0.002 and g/sub perpendicular/=2.0025 +- 0.0005, with strongly hindered motion even at room temperature, is assigned to an O/sup -//sub 2/ species located at the center of the structural cavity, U. The last center is a doublet with a 502.5 +- 0.5 Oe hyperfine splitting and g/sub iso/= 2.0022 +- 0.0001; it is due to H atoms located in U. Particular attention has been paid to the ''matrix'' ENDOR line at the free proton nuclear frequency and to the nature of the nuclear and electronic relaxation mechanisms that govern its shape and intensity. (AIP)

Research Organization:
Facultes Universitaires de Namur, Laboratoire de Catalyse, 61, rue de Bruxelles, Namur-B 5000, Belgium
OSTI ID:
7343453
Journal Information:
J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 65:3; ISSN JCPSA
Country of Publication:
United States
Language:
English

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