Super Hyperfine Research Articles

E.P.R. of trapped H atoms in γ-irradiated acidic glasses: Cross relaxation induced by Cu(II) organic complexes

Cross relaxation induced by Cu(II) organic complexes was observed, and the relative rates measured, for the trapped H atoms in γ-irradiated aqueous acidic glasses. Significant super hyperfine structure was also observed on both the g ⊥ and g ‖ components of the E.P.R. of Cu(II) complexes in the acidic glasses. Evidence is presented that such super hyperfine structure is due to axial interactions between the planar Cu(II) complexes and the water molecules or the H3O+ ions.

E.S.R. Investigation of 3d9 Ions in Alkali-Halides

Cu 2+ in NaCl, LiCl and NaF, and Ni + in NaCl, most of which were produced from Cu + and Ni 2+ by X-ray irradiation were studied by the e.s.r. All of Cu 2+ had elongated tetragonal surroundings, while Ni + had compressed ones. In NaCl: Cu 2+ , the optical dichroism along a cube edge was detected at 5 K corresponding to the Jahn-Teller distortion. From the observed super hyperfine structure of surrounding nuclei the amounts of covalency, f s and f σ were estimated as 0.77 to 0.89% and 7.9 to 12% in the chlorides, respectively. In the case of NaCl: Cu 2+ doped as divalent states, sharp anisotropic spectra without the hyperfine structure due to Cu nucleus were observed, which are presumably due to coagulated ions.

Die paramagnetische Elektronenresonanz (EPR) des Europiums (Eu2+) in Cadmiumfluorid

The EPR-parameters of Eu2+ substituted for Cd2+ in CdF2 have been measured at 300, 77 and 1,5°K. They are summarized in Table 1. The EPR spectrum is that of an S-state-ion in a cubic environment. As with Eu2+ inCaF2, SrF2 or BaF2 there is in CdF2 a superhyperfine (SHF) -interaction between the Eu2+- and F–-ions, which results mostly in an inhomogeneous broadening of the lines but sometimes in CdF2 in a splitting. There are some indications that the point charge model is not fully correct and that a slight deviation from the cubic environment does exist.

Electron Spin Resonance of the Organic Semiconductor, α-Copper Phthalocyanine

Various concentrations of polycrystalline powders of α-copper phthalocyanine diluted in nonparamagnetic α-metal-free phthalocyanine matrices have been studied by 8-mm ESR at room temperature. The superhyperfine (SHF) spin Hamiltonian used in analyzing earlier results of ESR investigations on square-bonded copper complexes has been reconsidered and a new SHF term is derived. The concentration-dependent study has revealed enough separate features to enable observations to be interpreted by essentially considering the contributions of only two molecular orientations to the over-all derivative line shape. Although single crystals of many organo-metallic complexes, including α-copper phthalocyanine, are not available, this study indicates that the relevant parameters of the spin Hamiltonian can in some cases be readily deduced from polycrystalline spectra.

ESR and ENDOR of Gamma-Irradiated AgNO3

Two paramagnetic species produced in AgNO 3 by gamma-irradiation at room temperature were identified to O 3 - and NO 2 , and direction cosines of principal axes of these centers with respect to the crystal axes were determined. From these results, it was confirmed that both O 3 - and NO 2 were trapped with definite directions in the NO 3 - vacancies and their radical planes were nearly the same as those of NO 3 - ions, but the definite directions of these two radicals are different from each other. Moreover, super hyperfine interactions of O 3 - with neighboring Ag nuclei were studied by ENDOR.

Electron paramagnetic resonance and nuclear spin echo in solutions of oxyfluorides of pentavalent molybdenum

1. Acid solutions of the salts (NH4)2[MoOF5], Zn[MoOF5], K2[MoOF5],and Cu[MoOF5] dissociate into the complex anion [MoOF5] and the cations K+, Zn2+, (NH4)+, and Cu2+. 2. In the complex anion [MoOF5]−2, a super hyperfine structure from the four F19 nuclei is observed as a result of the formation of covalent bonds of the ligands of F19 with the complex former. 3. The long lifetime of the ligands of F19 in the complex reduces the effectiveness of Mo(V) on the nuclear relaxation of F19; when the solution temperature is raised, the effectiveness increases as a result of the decrease in the lifetime of F19 in the complex. 4. In the complex [MoOF5]−2, the magnetic ion Mo(V) is found inside the octahedron formed from five covalently bonded atoms: four fluorine atoms and one oxygen atom. The fifth fluorine atom, situated in the transposition to the oxygen, possesses an ionic bond.