Structure and generation mechanism of Br centres in X‐rayed KBr

Elango, A.; Nurakhmetov, Т.N.

doi:10.1002/pssb.2220780211

Cited by 40 publications

(13 citation statements)

References 18 publications

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“…In these crystals isolated X;(D,) centres are formed on the basis of cation vacancies existing before X-irradiation and being distributed statistically uniformly in the crystal. It is well known [14] that the annealing of D, centres in the crystals investigated occurs in the temperature range from 300 to 390 K. This is in good agreement with the thermal annealing of X ; centres (300 to 370 K for KBr [8], 300 to 380 K for KCI [S]) created by X-irradiation at 80 K, when the probability of the production of large aggregates is small.…”

Section: Creation Of X; Centressupporting

confidence: 85%

Creation and Destruction of X Centres in Alkali Halides by X‐Radiation

Аkilbekov

Nurakhmetov

Elango

1980

Physica Status Solidi (b)

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The production (qand destruction efficiencies cf X, centres in NaCI, KCl, KBr, and KI by X-radiation versus the irradiation temperature (in the range of 80 to 320 K) are investigated by optical absorption and thermoluminescence methods. Both, the increase (80 to 150 K) and decrease (200 to 250 K) of qs3 in KBr and KI a t the adsorbed dose of lOlS to loz1 eV cm-3 are shown to be in correlation with the F-centre creation efficiency ( 7~) .I n chlorides q p does not decrease with qx7 and these crystals are characterized by 8 high defect creation efficiency at approximately room temperatures. It is supposed that the creation of large halogen aggregates is much more efficient in chlorides than in bromides and iodides.y 3)

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Section: Creation Of X; Centressupporting

confidence: 85%

Creation and Destruction of X Centres in Alkali Halides by X‐Radiation

Аkilbekov

Nurakhmetov

Elango

1980

Physica Status Solidi (b)

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“…In contrast to clustering process of F centers, which has been investigated by many authors, the aggregation of H centers is not well understood. Ho-wever, formation of interstitial halogen clusters under high-dose irradiation is confirmed by electronmicroscopic observations and optical studies [12,13]. Obviously, annealing leads to thermal decomposition of these aggregates by emitting of single H centers, which can annihilate with the generally much less mobile F centers, or decay on the surface by evolution a neutral halogen atom.…”

Section: Resultsmentioning

confidence: 56%

Hardening in LiF induced by fast Ni ions and recovery of properties under annealing

Manika

Maniks

Kūlis

et al. 2005

phys. stat. sol. (c)

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The recovery of hardness and optical absorbance of LiF crystals irradiated with 640 MeV nickel ions under annealing at 450-810 K is investigated. Recovery of the hardness of irradiated crystals is initiated at temperatures above 530 K, at which a transition from a complex absorption spectrum to a spectrum with only one broad peak at 275 nm is observed. Activation energy of 0.13 eV ± 0.02 eV, which is close to that necessary for migration of H centers, is obtained from the annealing data. -5]. However, so far the nature of radiation defects responsible for hardening (possibly small Li colloids, clusters of molecular fluorine and vacancies) is not clearly identified. A study of thermal stability of these defects and recovery of hardness and optical absorbance by thermal annealing of LiF crystals irradiated with fast nickel ions is reported hereafter.

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“…The efficiency of the destruction of Vzz(Pb2+) centres by electrons in RCl:PbCl, crystal is much less than that of V2,(Ca2+) or Vzz(Sr2f) centres, which have an effective positive charge [7]. Taking this fact into account and basing on the data of [l'i] on the face-centred position of the Pb2+ ion in a KC1:PbC12 crystal irradiated at 295 K the following structure of V2,(Pb2+) centres may be assumed (Fig.…”

Section: Structure Of the Centres Investigatedmentioning

confidence: 98%

Polarized Luminescence of Lead Ions Associated with Interstitial Radiation Defects in KCl:PbCl₂ Crsytals

Egemberdiev

Zazubovich

Nagirnyi

1982

Physica Status Solidi (b)

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Two types of lead ion and interstitial chlorine atom associates (H,(Pb2+) centres) are found and investigated by optical methods in X-irradiated KCl:PbCI, crystals. The polarized 3.35 and 1.8 eV emission of these centres and the absorption bands near 5.55 and 4.4 eV are caused by electronic transitions in the Pb3+ ion perturbed by CIT molecular ion, which occupies a cation vacancy and an anion site. The broad absorption band at 3.7 eV is due to the transitions in the C1, ion perturbed by Pb2+. Vsing the ESR data obtained by Schoemaker et al. it is concluded that the centres with 3.35 and 1.8 eV emission are interstitial chlorine atoms trapped by Pba+ ions associated with the nearest neighbouring (Hflol(Pbz+) centres) and with the next nearest neighbouring (H~100](Pb2t) centres) cation vacancies, respectively. Lead ion and Cl, molecular ion associates (Vez(Pbz') centres) are found. The polarized 3.05 eV emission and the 4.3 eV absorption band of these centres are caused by the electronic transitions in Pb2+ ions perturbed by C1; . The broad 5.27 eV absorption band is due to the electronic transitions in the Clz ions perturbed by PbS+.It is assumed that the VZz(Pb2+) centre may be represented as a Clz molecular ion which occupies two anion and one cation sites and is associated with a Pb2+ ion located (according to Itoh et al.) a t a face-centred position as well as with an interstitial chlorine ion and cation vacancy.

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Structure and generation mechanism of Br centres in X‐rayed KBr

Cited by 40 publications

References 18 publications

Creation and Destruction of X Centres in Alkali Halides by X‐Radiation

Creation and Destruction of X Centres in Alkali Halides by X‐Radiation

Hardening in LiF induced by fast Ni ions and recovery of properties under annealing

Polarized Luminescence of Lead Ions Associated with Interstitial Radiation Defects in KCl:PbCl₂ Crsytals

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Structure and generation mechanism of Br centres in X‐rayed KBr

Cited by 40 publications

References 18 publications

Creation and Destruction of X Centres in Alkali Halides by X‐Radiation

Creation and Destruction of X Centres in Alkali Halides by X‐Radiation

Hardening in LiF induced by fast Ni ions and recovery of properties under annealing

Polarized Luminescence of Lead Ions Associated with Interstitial Radiation Defects in KCl:PbCl2 Crsytals

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Polarized Luminescence of Lead Ions Associated with Interstitial Radiation Defects in KCl:PbCl₂ Crsytals