Nuclear magnetic resonance of 27Al in single crystals of NaMgAl(C2O4)3·xH2O

Zbieranowski, W.

doi:10.1016/0009-2614(75)87007-2

Cited by 4 publications

(3 citation statements)

References 8 publications

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“…To investigate this possibility we have burnt a spectral hole into the R 1 -line of the NaMgAl(ox) 3 ·8H 2 O:Cr(III) system. Previous work has shown that the 9 th water molecule in NaMgAl(ox) 3 ·9H 2 O can be reversibly removed at 98 °C without causing significant variations in the optical or macroscopic qualities of the crystal. ,, It has been suggested that the water molecule can move in to and out of the crystal through some channels within the structure . Upon the removal of the water molecule the 2 E splitting collapses from 20 cm -1 to ∼3 cm -1 and the R 1 -line shifts to 690.8 nm .…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, it was reported that the distortion from axial symmetry arises through the presence of one molecule of water of hydration for each [Cr(ox) 3 ] 3- complex. Upon removal of this water molecule, the Cr(III) EPR and the 27 Al NMR spectra become axial. , It was postulated that the ease of reversibility of the water removal is due to the presence of channels within the crystal structure …”

Section: Introductionmentioning

confidence: 99%

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Transient and Persistent Spectral Hole-Burning in the R-lines of Chromium(III) in NaMgAl(Oxalate)₃·9H₂O

Lewis

Riesen

2002

J. Phys. Chem. A

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The temperature dependence of transient and persistent spectral holes is reported for the R-lines (2E ← 4A2 transitions) in 4% chromium(III) doped NaMgAl(oxalate)3·9H2O. The temperature dependence is well described by taking into account two pseudolocal vibrations in a weak electron−phonon coupling model and the direct process between the two 2E levels. The persistent spectral hole-burning is based on a non photochemical mechanism involving mainly a rearrangement of a water molecule of crystallization. The 1.12 GHz width of the transient hole in the R2 line provides a value for the relaxation rate within the 2E multiplet, k(R2 → R1) = 3.5 × 109 s-1 at 2.5 K. The observed optical line width of Γ = 46 MHz for the R1-line at 2.5 K is most likely dominated by chromium(III)−chromium(III) spin−spin interactions. Spectral diffusion on the ms time scale causes persistent spectral holes to be significantly broader and holewidths of 260 MHz and 1.63 GHz for the R1 and R2-line, respectively, are observed. Spontaneous hole-filling is thermally activated and spectral diffusion on the minute time scale is slow in the investigated temperature range of 2.5−30 K.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Transient and Persistent Spectral Hole-Burning in the R-lines of Chromium(III) in NaMgAl(Oxalate)₃·9H₂O

Lewis

Riesen

2002

J. Phys. Chem. A

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“…Upon removal of this water molecule the Cr(III) EPR and the 27 Al NMR spectra become axial. 11, 12 It was suggested that the ease of reversibility of the water removal is due to the presence of channels within the crystal structure. 11 More recently, the crystal structure was again re-determined and the space group was refined to P 3c1.…”

Section: Introductionmentioning

confidence: 99%

Revisiting the crystal structure and thermal properties of NaMgAl(oxalate)3·9H2O/Cr(iii): an extraordinary spectral hole-burning material

Riesen

Rae

2008

Dalton Trans.

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We have reinvestigated the crystal structure and thermal properties of NaMgAl(oxalate)(3) x 9 H(2)O. In the thermal gravimetric analysis the steps of dehydration and decomposition/oxidation yield a mass change that is commensurate with 9 water molecules of hydration. Dehydration steps occur at 127, 171, and 201 degrees C whereas the oxalate ligand decomposes in steps at 403 and 424 degrees C with a final oxidation step at 692 degrees C. A refinement of the single crystal X-ray diffraction data taken at 200 K affirms the P3c1 space group with nine water molecules of hydration and unit cell parameters a = b = 16.7349(2) A and c = 12.6338(1) A with Z = 6. The structures can be described in terms of modulations of an idealised Z = 1 structure in P3lm. T-Cycle experiments of spectral holes in the R(1)-line yield a single Gaussian barrier with T(0) +/- sigma(T) of 46 +/- 21 K and three barriers with 40 +/- 12, 70 +/- 10, 107 +/- 5 K for perprotonated and partially deuterated (46%) NaMgAl(oxalate)(3) x 9 H(2)O/Cr(III) 0.5%, respectively.

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13 Aluminum

Chihara¹,

Nakamura²

Nuclei D - Cl

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Nuclear magnetic resonance of 27Al in single crystals of NaMgAl(C2O4)3·xH2O

Cited by 4 publications

References 8 publications

Transient and Persistent Spectral Hole-Burning in the R-lines of Chromium(III) in NaMgAl(Oxalate)₃·9H₂O

Transient and Persistent Spectral Hole-Burning in the R-lines of Chromium(III) in NaMgAl(Oxalate)₃·9H₂O

Revisiting the crystal structure and thermal properties of NaMgAl(oxalate)3·9H2O/Cr(iii): an extraordinary spectral hole-burning material

13 Aluminum

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Nuclear magnetic resonance of 27Al in single crystals of NaMgAl(C2O4)3·xH2O

Cited by 4 publications

References 8 publications

Transient and Persistent Spectral Hole-Burning in the R-lines of Chromium(III) in NaMgAl(Oxalate)3·9H2O

Transient and Persistent Spectral Hole-Burning in the R-lines of Chromium(III) in NaMgAl(Oxalate)3·9H2O

Revisiting the crystal structure and thermal properties of NaMgAl(oxalate)3·9H2O/Cr(iii): an extraordinary spectral hole-burning material

13 Aluminum

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Transient and Persistent Spectral Hole-Burning in the R-lines of Chromium(III) in NaMgAl(Oxalate)₃·9H₂O

Transient and Persistent Spectral Hole-Burning in the R-lines of Chromium(III) in NaMgAl(Oxalate)₃·9H₂O