Die Fluoreszenz von Z1-Zentren in KCl

Paus, H. J.

doi:10.1007/bf01392579

Cited by 19 publications

(7 citation statements)

References 1 publication

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“…As with the F-centers, the calculated Z,-transition energies do not lie on the Mollwo line (see Fig. 6) which is found experimen-\,, [7]. The enormous gap in energy between the pL-and p,,-states in the point-ion calculation is closed (see Fig.…”

Section: Discussionmentioning

confidence: 63%

“…Therefore, the so-called model I is given further theoretical support. Still there is a relative big energy difference between E , and E,zl: about 0.6 eV intheory as compared with 0.11 eV of Paus [7]. We have investigated what the effect of a displacement of the cation impurity would be.…”

Section: Discussionmentioning

confidence: 98%

“…They get an approximate pseudopotential v, = VPI + 2 [ A , + (V -U , ) 4 1 6 (rr y ) 3 (1.1) 7 where VpI is the point-ion potential, U, is the potential a t the ion y due to the where P is the projection operator for the ion states p = 2 l y e > t 1. 5) i and N is the normalizing constant.…”

Section: Introductionmentioning

confidence: 99%

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F‐, F_A‐ and Z₁‐Center Calculations Using Approximate Pseudopotentials

Weber¹,

Dick²

1969

Physica Status Solidi (b)

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The authors carried out variational calculations on F-, FA-, and Z,-centers, using a technique which was proposed by Bartram, Stoneham, and Gash. To illustrate how the method works, ionization potentials of alkali atoms are calculated for different trial wave functions. Plausible criteria are used to limit the choice of wave functions in a manner which avoids the necessity of using experimentally determined parameters. The agreement with F-, F-k-, and Z,-data is good. For the Z,-center, the experimentally favored so-called model I is given further theoretical support. Moreover, there is found evidence for a possible displacement of the divalent cation impurity of the Z,-complex.Die Autoren fuhrten Variationsrechnungen fur F-, F Aund Z,-Zentren durch, wobei sie ein von Bartram, Stoneham und Gash vorgeschlagenes Verfahren benutzten. Urn dessen II'irkungsweise zu zeigen, werden Ionisationspotentiale von Alkalihalogeniden mit verschiedenen Versuchswellenfunktionen berechnet. Aus Plausibilitatsuberlegungen wird die M'ahl der Wellenfunktionen beschrankt, so daO keine experimentell bestimmten Parameter verwendet werden mussen. Die Ubereinstimmung mit den experimentellen F-, FAund %,-Ubergangsenergien ist gut. Das sogenannte Model1 I fur das Z,-Zentrum, das vom Experiment bevorzugt wird, erhalt weitere theoretische Bestatigung. Ferner werden Hinweise fhr eine mogliche Verschiebung des zweiwertigen Fremdkations im Z,-Komplex gefunden. Theoretical Fand FA-energies for the first excited state due to Gourary-Adrian type I and I1 wave functions. The second column shows the cor-

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Section: Discussionmentioning

confidence: 63%

Section: Discussionmentioning

confidence: 98%

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F‐, F_A‐ and Z₁‐Center Calculations Using Approximate Pseudopotentials

Weber¹,

Dick²

1969

Physica Status Solidi (b)

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“…FA (/)) as well as for the Z1 centre [19,20] (i.e. for an F-centre perturbed by a monovalent or divalent impurity respectively) are close to the O~T ones.…”

Section: H~l) E(t) = E(o) -B Ctgh ~ (2) ( Ho~2 ) H 2 (T) = H 2 (0) mentioning

confidence: 87%

Speculations on the absorption and emission properties of the F-centre in alkali halides

Bosi

Nimis

1991

Il Nuovo Cimento D

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(ricevuto il 21 Febbraio 1991; revisionato il 18 Luglio 1991; approvato il 29 Luglio 1991) Summary. --A review of acquisitions and of unresolved problems concerning Fcentres in alkali halides is presented. The main conclusions are a) the temperature dependence of the bands is mainly due to the thermal expansion for the absorption process and to electron-phonon interaction for the emission process: for the latter half-width and Huang-Rhys factor values are related to the transverse optical frequency ones; b) the lifetime VR of the relaxed excited state is not intrinsic at low temperature because of the interaction between F-and a-centres always present in real samples; c) even though the absolute quantum yield decreases when F-centre concentration increases, the relative quantum yield vr is unaffected by change on F-centre concentration, strongly evidencing a nonhomogeneous distribution of F-centres in real samples; d) a temperature-dependent fine structure in zR (an Vr) values is observed but only when temperature control of the samples is better than a few hundredth of a degree: this effect has been interpreted in terms of interactions which involve F-, a-and F'-centres. PACS 61.70 -Defects in crystals. PACS 61.70.Dx -Colour centres.

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“…Table 1 gives a list of relevant facts regarding these impurities. It can be seen from Table 1 [20]. I 0 B centre; A Z, (Ca); 0 Z, (Sr); 0 Z1 (Ea) 28 26 24 second-ionization potentials than the other impurities which means that impurities of the former group trap electrons less effectively than negative ion vacancies and the other set of impurities.…”

Section: Optical Propertics Of Z Centresmentioning

confidence: 99%