The optically detected magnetic resonance of nickel‐doped silver chloride

Marchetti, Alfred P.; Scozzafava, M.

doi:10.1002/pssb.2220960147

Cited by 7 publications

(2 citation statements)

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“…19 The influence of the 3d−4s mixing on the equilibrium geometry of Cu 2+ complexes has previously been suggested by several authors. 24−28 Although Ni + is an unusual oxidation state for nickel, such a valence has been stabilized in lattices like LiF, 29 NaF, 29 KZnF 3 , 30 KMgF 3 , 31 CsCaF 3 , 32 or AgCl 33,34 initially doped with Ni 2+ and subsequently irradiated with X-rays or UV rays. Nevertheless, in Bridgman-grown crystals of NaCl doped with divalent nickel, EPR experiments by Shengelaya et al 15 have undoubtedly proven the formation of Ni + impurities without irradiating the samples.…”

Section: Introductionmentioning

confidence: 99%

Origin of Small Barriers in Jahn–Teller Systems: Quantifying the Role of 3d–4s Hybridization in the Model System NaCl:Ni⁺

Barriuso¹,

Ortiz-Sevilla²,

Aramburu³

et al. 2013

Inorg. Chem.

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Despite its relevance, the microscopic origin of the energy barrier, B, between the compressed and elongated geometries of Jahn−Teller (JT) systems is not well understood yet because of a lack of quantitative data about its various contributions. Seeking to clear up this matter, we have carried out both periodic and cluster ab initio calculations on the model system NaCl:Ni + . This system is particularly puzzling because, according to experimental data, its barrier is much smaller than that for other d 9 and d 7 ions in similar lattices. All calculations performed on the model system lead, in fact, to values |B| ≤ 160 cm −1 , which are certainly smaller than B = 500 cm −1 derived for NaCl:M 2+ (M = Ag, Rh) or B = 1024 cm −1 obtained for KCl:Ag 2+ . As a salient feature, analysis of calculations carried out as a function of the Q θ (∼3z 2 − r 2 ) coordinate unveils the microscopic origin of the barrier. It is quantitatively proven that the elongated geometry observed for NaCl:Ni + is due to the 3d−4s vibronic admixture, which is slightly larger than the anharmonicity in the e g JT mode that favors a compressed geometry. The existence of these two competing mechanisms explains the low value of B for the model system, contrary to cases where the complex formed by d 9 or d 7 ions is elastically decoupled from the host lattice. Although the magnitude of B for NaCl:Ni + is particularly small, the tunneling splitting, 3Γ, is estimated to be below 9 cm −1 , thus explaining why the coherence is easily destroyed by random strains and thus a static JT effect is observed experimentally. As a main conclusion, the barrier in JT systems cannot be understood neglecting the tiny changes of the electronic density involved in small distortions. The present calculations reasonably explain the experimental g tensor of NaCl:Ni + , pointing out that the d−d transitions in NiCl 6 5− are much smaller than those for CuCl 6 4− and the optical electronegativity of Ni + is only around 1.

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Section: Introductionmentioning

confidence: 99%

Origin of Small Barriers in Jahn–Teller Systems: Quantifying the Role of 3d–4s Hybridization in the Model System NaCl:Ni⁺

Barriuso¹,

Ortiz-Sevilla²,

Aramburu³

et al. 2013

Inorg. Chem.

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“…The g-values of the Ni+(tetra) defect reported in literature show some scatter.This is especially the case for those obtained in Hohne et al's experiment. One also sees that because of the different symmetry and g-values, Marchetti and Scoyzafava [8] did not observe a Ni+(ortho) defect as reported, but a Ni+(tetra) defect.…”

Section: Analysis Of the Spectra Below 50 Kmentioning

confidence: 69%

Electron Spin Resonance Study of Ni²⁺ Centers in AgCl(Cu, Ni)

Robbroeck

Bouwen

Schoemaker

1985

Physica Status Solidi (b)

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Single AgCl crystals doped with Cu2+ and Ni2+ were studied by means of electron spin resonance. As grown crystals contain three different Ni2+ centers which reduce to Ni+ defects under illumination at 50 K with blue light. Six Nit defects were found with tetragonal, orthorhombic, and cubic symmetry. At 101 K the orthorhombic centers transform to the tetragonal defects. The latter become thermally unstable at 135 K and induce the decay of the Cu2+ centers.Mit Cu2+ und Ni2+ dotierte AgC1-Einkristalle werden mittels E P R untersucht. Jungfrauliche Kristalle enthalten drei verschiedene Ni2+-Zentren, die unter Bestrahlung mit blauem Licht bei 50 K zu Ni+-Defekten reduziert werden. Sechs Ni+-Defekte mit tetragonaler, orthorhombischer und kubischer Symmetrie werden gefunden. Bei 101 K werden die orthorhombischen Zentren in tetragonale Defekte transformiert. Letztere werden bei 135 K instabil und verursachen den Zerfall der Cuz+-Zentren.

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The Photochemistry and Photophysics of the Silver Halides

Marchetti

Eachus

1992

Advances in Photochemistry

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The optically detected magnetic resonance of nickel‐doped silver chloride

Abstract: Optically detected magnetic resonance is observed in nickel-doped AgCl a t liquid-helium temperatures. The species found is thought to be [ (NiC16)

Cited by 7 publications

References 11 publications

Origin of Small Barriers in Jahn–Teller Systems: Quantifying the Role of 3d–4s Hybridization in the Model System NaCl:Ni⁺

Origin of Small Barriers in Jahn–Teller Systems: Quantifying the Role of 3d–4s Hybridization in the Model System NaCl:Ni⁺

Electron Spin Resonance Study of Ni²⁺ Centers in AgCl(Cu, Ni)

The Photochemistry and Photophysics of the Silver Halides

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The optically detected magnetic resonance of nickel‐doped silver chloride

Abstract: Optically detected magnetic resonance is observed in nickel-doped AgCl a t liquid-helium temperatures. The species found is thought to be [ (NiC16)

Cited by 7 publications

References 11 publications

Origin of Small Barriers in Jahn–Teller Systems: Quantifying the Role of 3d–4s Hybridization in the Model System NaCl:Ni+

Origin of Small Barriers in Jahn–Teller Systems: Quantifying the Role of 3d–4s Hybridization in the Model System NaCl:Ni+

Electron Spin Resonance Study of Ni2+ Centers in AgCl(Cu, Ni)

The Photochemistry and Photophysics of the Silver Halides

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Product

Resources

About

Origin of Small Barriers in Jahn–Teller Systems: Quantifying the Role of 3d–4s Hybridization in the Model System NaCl:Ni⁺

Origin of Small Barriers in Jahn–Teller Systems: Quantifying the Role of 3d–4s Hybridization in the Model System NaCl:Ni⁺

Electron Spin Resonance Study of Ni²⁺ Centers in AgCl(Cu, Ni)