Stimulated Spin-Echo Measurement of Cross-Relaxation in Neutron-Irradiated Calcite

Wanlass, L.K.; Wakabayashi, Jiro

doi:10.1103/physrevlett.6.271

Cited by 7 publications

(2 citation statements)

References 5 publications

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“…These radicals, especially CO − 2 , can have a very long lifetime in calcite (of the order of 10 6 years at room temperature) and can be used for ESR dating in geochronology [8]. The ESR signal of CO − 2 radicals allows ESR dating up to 1 million years, which spans the time interval where 14 C-dating (5 × 10 4 years maximum limit) and K-Ar-dating (10 5 years minimum limit) are not applicable. The lifetime of stable carbonate radicals can be reduced by impurities (like water molecules or inclusions), which are diffusive in the calcite structure.…”

Section: Introductionmentioning

confidence: 99%

“…Electron spin relaxation of free radicals in calcite has not been studied so far, except some preliminary experiments of low sensitivity performed at very low temperatures, which proved that an electron spin echo (ESE) signal can be generated [13,14]. The ESE decay has been measured in aragonite only, and the phase memory time (spinspin relaxation time) was determined as 1.58 μs at room temperature [15].…”

Section: Introductionmentioning

confidence: 99%

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Dynamics of CO₂⁻radiation defects in natural calcite studied by ESR, electron spin echo and electron spin relaxation

Wencka¹,

Lijewski

Hoffmann

2008

J. Phys.: Condens. Matter

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ESR spectra were recorded in the X-band (9.6 GHz) and in the W-band (94 GHz) and electron spin relaxation was measured by electron spin echo (ESE) in the temperature range 4.2–300 K for radicals in natural calcite samples obtained from a cave stalactite and a dripstone layer. Four types of carbonate radical spectra and two sulfate radical spectra were identified and high accuracy g-factors were derived. Time and temperature behaviour of the spectra show that the dominating CO2− radicals are rigidly bonded or undergo free reorientations, whereas CO3−, SO2− and SO3− only undergo free reorientations. Below 200 K the free reorientations of CO2− are suppressed and a hindered rotation around single local axis appears. The ESE detected spectrum proves that the lines of free rotating radicals are homogeneously broadened, thus they cannot participate in electron spin echo formation. Spin–lattice relaxation data show that CO2− radicals are decoupled from lattice phonons and relax via local mode tunnelling motion between inequivalent oxygen positions of CO2− molecules. The tunnelling appears in two excited vibrational states of energy 71 and 138 cm−1. Librational motions of CO2− molecules were detected by electron spin echo decay (phase relaxation) with energy 153 cm−1. Two kinds of impurity hydrogen atoms were distinguished from ESEEM: in-water inclusions and water coordinated to the calcium ions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dynamics of CO₂⁻radiation defects in natural calcite studied by ESR, electron spin echo and electron spin relaxation

Wencka¹,

Lijewski

Hoffmann

2008

J. Phys.: Condens. Matter

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The Generation and Detection of Electron Spin Echoes

Bender

2004

EPR: Instrumental Methods

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Biological Applications of Time Domain ESR

Thomann

Dalton

1984

Biological Magnetic Resonance

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Stimulated Spin-Echo Measurement of Cross-Relaxation in Neutron-Irradiated Calcite

Cited by 7 publications

References 5 publications

Dynamics of CO₂⁻radiation defects in natural calcite studied by ESR, electron spin echo and electron spin relaxation

Dynamics of CO₂⁻radiation defects in natural calcite studied by ESR, electron spin echo and electron spin relaxation

The Generation and Detection of Electron Spin Echoes

Biological Applications of Time Domain ESR

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Stimulated Spin-Echo Measurement of Cross-Relaxation in Neutron-Irradiated Calcite

Cited by 7 publications

References 5 publications

Dynamics of CO2−radiation defects in natural calcite studied by ESR, electron spin echo and electron spin relaxation

Dynamics of CO2−radiation defects in natural calcite studied by ESR, electron spin echo and electron spin relaxation

The Generation and Detection of Electron Spin Echoes

Biological Applications of Time Domain ESR

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Product

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Dynamics of CO₂⁻radiation defects in natural calcite studied by ESR, electron spin echo and electron spin relaxation

Dynamics of CO₂⁻radiation defects in natural calcite studied by ESR, electron spin echo and electron spin relaxation