Energy features of bound polaron states in colored NaCl and KBr crystals

Korovkin, E. V.; Lebedkina, Tatiana

doi:10.1134/1.1307051

Cited by 3 publications

(8 citation statements)

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“…The spectra were measured at T = 100-400 K because the photoconductivity due to polaron-type traps found earlier [1][2][3] is so high below 90 K that the signal from dislocations is essentially hidden against this background. The lifetime of electrons in polaron-type traps in NaCl crystals becomes negligible in the temperature range used for tests, so that they have time to be thermally emptied before the beginning of the photoconductivity measurement.…”

Section: Experimental Techniquementioning

confidence: 99%

“…(i) Filling of electron states: The specimen is subjected to F-light for 30 s. In comparison with the earlier works [1][2][3], the F-light spectrum was broadened toward longer wavelengths, up to 690 nm at the 50% transmission level and 740 nm at the 10% transmission level (a SI-8 tungsten lamp and SZS-25 filter were used). The optimal duration of the primary irradiation was found to be 30 s. Further illumination led to a minor increase in the IR photoconductivity signal.…”

Section: Experimental Techniquementioning

confidence: 99%

“…Using this method, the authors revealed and investigated the F-light stimulated infrared photoconductivity of electron traps of polaron type in colored alkali-halide crystals (NaCl, KCl, KBr ) [2].…”

Section: Introductionmentioning

confidence: 99%

“…Further illumination of the sample by infrared light, results in infrared photoconductivity generated by electrons that leave traps and find themselves in the conduction band. Therefore, the infrared photoconductivity stimulated by F-light is a convenient technique for the investigation of electron traps in colored alkali-halide crystals [1,2]. It is schematically shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

“…The photoconductivity technique was first developed in 1987 [3] and was being improved since then. Using this method, the authors revealed and investigated the F-light stimulated infrared photoconductivity of electron traps of polaron type in colored alkali-halide crystals (NaCl, KCl, KBr ) [2].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Plastic-strain induced peaks in the spectrum of F-light-stimulated photoconductivity in colored NaCl crystals

Lebedkina

Korovkin

2004

Materials Science and Engineering: A

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Section: Experimental Techniquementioning

confidence: 99%

Section: Experimental Techniquementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Plastic-strain induced peaks in the spectrum of F-light-stimulated photoconductivity in colored NaCl crystals

Lebedkina

Korovkin

2004

Materials Science and Engineering: A

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Detection of defects binding free polarons in colored alkali halide crystals

Korovkin

2017

Phys. Solid State

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Gas-phase Condensation of Carbonated Silicate Grains

Rouillé,

Schmitt,

Jäger

et al. 2024

ApJ

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Reports on the detection of carbonates in planetary nebulae (PNe) and protostars have suggested the existence of a mechanism that produces these compounds in stellar winds and outflows. A subsequent laboratory study has reported a possible mechanism by presenting the non-thermodynamic-equilibrium (TE), gas-phase condensation of amorphous silicate grains with amorphous calcium carbonate inclusions. The authors concluded that water vapor was necessary for the formation of the carbonates. We present a laboratory study with pulsed laser ablation of a MgSi target in O2 and CO2 gases and report, in the absence of water vapor, the non-TE, gas-phase condensation of amorphous carbonated magnesium silicate dust. It consists of amorphous silicate grains with the formula MgSiO3, which comprise carbonate groups homogeneously dispersed in their structure. The IR spectra of the grains show the characteristic bands of amorphous silicates and two bands at ∼6.3 and ∼7.0 μm, which we assign to the carbonate groups. The silicate bands are not significantly affected at an estimated Si:C ratio of 9:1–9:2. Such grains could form in winds and outflows of evolved stars and PNe if C atoms are present during silicate condensation. Additionally, we find that Lyα radiation dissociates the carbonate groups at the surface of the carbonated silicate grains and we estimate the corresponding photodissociation cross section of (0.04 ± 0.02) ×10−16 cm2. Therefore, photodissociation would limit the formation of carbonate groups on grains in winds and outflows of stars emitting vacuum ultraviolet photons, and the carbonates observed in protostars have not formed by gas-phase condensation.

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Energy features of bound polaron states in colored NaCl and KBr crystals

Cited by 3 publications

References 8 publications

Plastic-strain induced peaks in the spectrum of F-light-stimulated photoconductivity in colored NaCl crystals

Plastic-strain induced peaks in the spectrum of F-light-stimulated photoconductivity in colored NaCl crystals

Detection of defects binding free polarons in colored alkali halide crystals

Gas-phase Condensation of Carbonated Silicate Grains

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