Electron paramagnetic resonance of PO 3 2? and SO 3 ? radicals in anhydrite, celestite and barite: the hyperfine structure and dynamics

Ryabov, I. D.; Bershov, L. V.; Speranskiy, A. V.; Ganeev, I. G.

doi:10.1007/bf01204322

Cited by 28 publications

(12 citation statements)

References 9 publications

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“…Their concentration turns out to be small and near to that of the corresponding isoelectronic 33SO;-and 33SO2 radicals containing the rare isotope 33S with natural abundance 0.75% (see, for example, EPR spectrum in Fig. 2 in the work of Ryabov et al 1983). As an exception, one of the two PO~-radicals in CaSO4 showed a concentration more than 10-fold higher.…”

Section: Introductionmentioning

confidence: 82%

“…In celestite and barite the multiplicity was KM= 2; g and A tensors have only one coinciding principal axis parallel to the crystallographic axis b. As follows from Table 4 of Ryabov et al (1983), such values of K ~t and directions of the principal axes of the g and A tensors are inherent in paramagnetic centers localized in c position with point group 2 mm (the number of the translationally inequivalent points in the unit cell is K~ = 2) in space group Aroma for anhydrite, and in c position with point group m (K~--4) in space group Pnma for celestite and barite. The point group of the SO4 tetrahedra is just the same, i.e.…”

Section: Identification Of Paramagnetic Centermentioning

confidence: 95%

“…2 mm for anhydrite and m for celestite and barite. Two of the magnetic axes of a tetrahedral radical AB4 with the point symmetry 2 mm are known to be directed along the tetrahedron edges which couple the B atoms arranged symmetrically about the m planes, and the third magnetic axis goes through the middles of those edges (Atkins and Symons 1967 Table 3 in work of Ryabov et al 1983). The directions of A and g principal axes of the investigated paramagnetic center in CaSO4 are just the same.…”

Section: Identification Of Paramagnetic Centermentioning

confidence: 96%

“…Previous EPR investigations on natural waterless sulphates of Ca, Sr and Ba (Ryabov et al 1983(Ryabov et al , 1989 showed the presence of the phosphorous paramagnetic defects PO~-and PO 2-ionic radicals. Their concentration turns out to be small and near to that of the corresponding isoelectronic 33SO;-and 33SO2 radicals containing the rare isotope 33S with natural abundance 0.75% (see, for example, EPR spectrum in Fig.…”

Section: Introductionmentioning

confidence: 98%

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EPR and ENDOR of the PO 4 2? radical in anhydrite, celestite and barite

Ryabov¹,

Potashnyi²

1992

Phys Chem Minerals

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Abstract. Electron paramagnetic resonance (EPR) andelectron nuclear double resonance (ENDOR) low temperature measurements of natural anhydrite CaSO4, celestite SrSO4 and barite BaSO 4 have revealed the presence of PO 2-radical. The principal values of the g tensor and the A tensor [MHz] of hyperfine interaction (HFI) are found to be gxx=2.0124, gyy=2.0159, g~z=2.0098, Axx= 82.1, Ayy--81.4, A~z=77.2 in CaSO4, g~=2.0250, gyy=2.0070, g~z=2.0131, A~=84.8, Ayy=82.7, Az~ =90.5 in SrSO4, gx~=2.0302, gyy=2.0079, g~z=2.0135, A~ = 85.2, Ayy --82.3, A~ = 90.0 in BaSO4. The principal axes Axe, Ayy and A~= are parallel to the crystallographic axes a, b, c in all three matrices. In anhydrite the principal g axes coincide with the A axes. In celestite and barite such coincidence is found to be only along the b axis (a low symmetry effect). The coherence effect of splitting of ENDOR lines by a strong microwave field has been detected. From the analysis of the relative intensities of the ENDOR lines of the PO~-radical in CaSO4 the relation of probabilities of cross-relaxation processes W~/W~ = 3.5 are evaluated.

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Section: Introductionmentioning

confidence: 82%

Section: Identification Of Paramagnetic Centermentioning

confidence: 95%

Section: Identification Of Paramagnetic Centermentioning

confidence: 96%

Section: Introductionmentioning

confidence: 98%

See 2 more Smart Citations

EPR and ENDOR of the PO 4 2? radical in anhydrite, celestite and barite

Ryabov¹,

Potashnyi²

1992

Phys Chem Minerals

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“…The point symmetry of the SO~-and PO~-radicals in barite is m. Therefore, for them as well as for the SO3 radical (Ryabov et al 1983) a low symmetry effect is observed implying a noncoincidence of the principal axes of the g-and A-tensors in the ac plane. For the PO22-radical (where the angle between z and z' axes equals to 12 ~ this effect is more pronounced than for the SO~ radical (5~ Schneider et al (1966) were able to determine the signs of the HFI constants of the SOy radical in KC1 by averaging the dipole-dipole electron-nuclear interaction to zero at the room temperature.…”

Section: Model Of Po~-and So; Centersmentioning

confidence: 88%