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Modeling equilibrium concentrations of Bjerrum and molecular point defects and their complexes in ice Ih
- Source :
- Repositório da Produção Científica e Intelectual da Unicamp, Universidade Estadual de Campinas (UNICAMP), instacron:UNICAMP
- Publication Year :
- 2008
-
Abstract
- We present a model for the determination of the thermal equilibrium concentrations of Bjerrum defects, molecular point defects, and their aggregates in ice Ih. First, using a procedure which minimizes the free energy of an ice crystal with respect to the numbers of defect species, we derive a set of equations for the equilibrium concentrations of free Bjerrum and point defects, as well their complexes. Using density-functional-theory calculations, we then evaluate the binding energies of Bjerrum-defect/vacancy and Bjerrum-defect/interstitial complexes. In contrast to the complexes which involve the molecular vacancy, the results suggest that the molecular interstitial binds preferentially to the D-type Bjerrum defect. Using both theoretical binding and formation free energies as well as the available experimental data, we find that the preferential binding and the substantial presence of the interstitial as the predominant point defect in ice Ih may lead to conditions in which the number of free D defects becomes considerably smaller than that of free L defects. Such a scenario could possibly be involved in the experimentally observed inactivity of D-type Bjerrum defects in the electrical properties of ice Ih FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPES Fechado
- Subjects :
- Thermal equilibrium
Ice crystals
Chemistry
Lead (sea ice)
Binding energy
General Physics and Astronomy
Ice Ih
Thermodynamics
Molecular modeling
Crystallographic defect
Teoria do funcional de densidade
Gelo hexagonal
Bjerrum defect
Crystallography
Vacancy defect
Density functional theory
Artigo original
Modelagem molecular
Physical and Theoretical Chemistry
Hexagonal ice
Subjects
Details
- Database :
- OpenAIRE
- Journal :
- Repositório da Produção Científica e Intelectual da Unicamp, Universidade Estadual de Campinas (UNICAMP), instacron:UNICAMP
- Accession number :
- edsair.doi.dedup.....6a689e46ac5cfbb34c31c68362777af5