Fast diffusion of the off-center impurities Cu+ and Li+ in the KCI lattice

F. Despa, V. Topa

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

In this work, we perform a study of the off-center effect on the diffusion coefficient and we propose a new mechanism for fast diffusion. The model assumes that the equilibrium positions of the cationic impurities are noncentral and that the diffusion proceeds by hopping across the potential barrier along the nonlinear paths with the highest probability [1]. The nonlinear paths between two consecutive positions characterize even the self-diffusion and furthermore, in the off-center diffusion this path is appropriate. The main results is that the off-center position considerably enhances the diffusion. The theoretical diffusion coefficients have been obtained by modeling the potential barrier. Changes of the configuration entropy and the vibration spectra due to the presence of the noncentral impurity are included in the model. We emphasize the good agreement of the model with the experimental data for KCl:Cu+ and show that if the impurity is placed close to the central site, the appropriate diffusion coefficient is close to that for the cationic self-diffusion. We proceeded in the Li+ cation case as in the case of Cu+ cation.

Original languageEnglish (US)
Pages (from-to)299-303
Number of pages5
JournalRadiation Effects and Defects in Solids
Volume137
Issue number1 -4 pt 4
StatePublished - 1995
Externally publishedYes

Fingerprint

Impurities
impurities
diffusion coefficient
cations
Cations
entropy
Positive ions
vibration
configurations
Entropy

ASJC Scopus subject areas

  • Nuclear Energy and Engineering
  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Radiation

Cite this

Fast diffusion of the off-center impurities Cu+ and Li+ in the KCI lattice. / Despa, F.; Topa, V.

In: Radiation Effects and Defects in Solids, Vol. 137, No. 1 -4 pt 4, 1995, p. 299-303.

Research output: Contribution to journalArticle

@article{a78810c335db4effadf2791c271488f4,
title = "Fast diffusion of the off-center impurities Cu+ and Li+ in the KCI lattice",
abstract = "In this work, we perform a study of the off-center effect on the diffusion coefficient and we propose a new mechanism for fast diffusion. The model assumes that the equilibrium positions of the cationic impurities are noncentral and that the diffusion proceeds by hopping across the potential barrier along the nonlinear paths with the highest probability [1]. The nonlinear paths between two consecutive positions characterize even the self-diffusion and furthermore, in the off-center diffusion this path is appropriate. The main results is that the off-center position considerably enhances the diffusion. The theoretical diffusion coefficients have been obtained by modeling the potential barrier. Changes of the configuration entropy and the vibration spectra due to the presence of the noncentral impurity are included in the model. We emphasize the good agreement of the model with the experimental data for KCl:Cu+ and show that if the impurity is placed close to the central site, the appropriate diffusion coefficient is close to that for the cationic self-diffusion. We proceeded in the Li+ cation case as in the case of Cu+ cation.",
author = "F. Despa and V. Topa",
year = "1995",
language = "English (US)",
volume = "137",
pages = "299--303",
journal = "Radiation Effects and Defects in Solids",
issn = "1042-0150",
publisher = "Taylor and Francis Ltd.",
number = "1 -4 pt 4",

}

TY - JOUR

T1 - Fast diffusion of the off-center impurities Cu+ and Li+ in the KCI lattice

AU - Despa, F.

AU - Topa, V.

PY - 1995

Y1 - 1995

N2 - In this work, we perform a study of the off-center effect on the diffusion coefficient and we propose a new mechanism for fast diffusion. The model assumes that the equilibrium positions of the cationic impurities are noncentral and that the diffusion proceeds by hopping across the potential barrier along the nonlinear paths with the highest probability [1]. The nonlinear paths between two consecutive positions characterize even the self-diffusion and furthermore, in the off-center diffusion this path is appropriate. The main results is that the off-center position considerably enhances the diffusion. The theoretical diffusion coefficients have been obtained by modeling the potential barrier. Changes of the configuration entropy and the vibration spectra due to the presence of the noncentral impurity are included in the model. We emphasize the good agreement of the model with the experimental data for KCl:Cu+ and show that if the impurity is placed close to the central site, the appropriate diffusion coefficient is close to that for the cationic self-diffusion. We proceeded in the Li+ cation case as in the case of Cu+ cation.

AB - In this work, we perform a study of the off-center effect on the diffusion coefficient and we propose a new mechanism for fast diffusion. The model assumes that the equilibrium positions of the cationic impurities are noncentral and that the diffusion proceeds by hopping across the potential barrier along the nonlinear paths with the highest probability [1]. The nonlinear paths between two consecutive positions characterize even the self-diffusion and furthermore, in the off-center diffusion this path is appropriate. The main results is that the off-center position considerably enhances the diffusion. The theoretical diffusion coefficients have been obtained by modeling the potential barrier. Changes of the configuration entropy and the vibration spectra due to the presence of the noncentral impurity are included in the model. We emphasize the good agreement of the model with the experimental data for KCl:Cu+ and show that if the impurity is placed close to the central site, the appropriate diffusion coefficient is close to that for the cationic self-diffusion. We proceeded in the Li+ cation case as in the case of Cu+ cation.

UR - http://www.scopus.com/inward/record.url?scp=0029530388&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0029530388&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0029530388

VL - 137

SP - 299

EP - 303

JO - Radiation Effects and Defects in Solids

JF - Radiation Effects and Defects in Solids

SN - 1042-0150

IS - 1 -4 pt 4

ER -