scholarly journals Linear thermal expansion data for tuffs from the unsaturated zone at Yucca Mountain, Nevada; Yucca Mountain Site Characterization Project

1992 ◽  
Author(s):  
B.M. Schwartz ◽  
C.S. Chocas
Keyword(s):  
Thermal Expansion ◽  
Unsaturated Zone ◽  
Linear Thermal Expansion ◽  
Site Characterization ◽  
Yucca Mountain ◽  
Thermal Expansion Data ◽  
Mountain Site

Calculation of Defect Formation Energy from the Thermal Expansion Data for Lead Fluoride

1994 ◽  
Vol 369 ◽  
Author(s):  
Brenda J. Schuler ◽  
T. S. Aurora ◽  
D. O. Pederson ◽  
S. M. Day
Keyword(s):  
Thermal Expansion ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Formation Energy ◽  
Defect Formation ◽  
Coefficient Of Thermal Expansion ◽  
Linear Thermal Expansion ◽  
Lead Fluoride ◽  
Defect Formation Energy ◽  
Thermal Expansion Data

AbstractLead fluoride is a superionic conductor with the fluorite structure. Results of the measurement of linear thermal expansion of lead fluoride (reported earlier in literature) showed a large increase in the thermal expansion coefficient near 700 K where the ionic conductivity has been shown to exhibit a sharp increase. It is believed that thermally-generated defects in a crystal lattice affect the thermal expansion coefficient. This idea was applied in the present analysis to calculate the defect formation energy (Ef) by using the literature values of the coefficient of thermal expansion. It was assumed that the thermal expansion in excess of that produced due to the lattice anharmonicity (δ∝) is proportional to the concentration of defects (n). With this assumption, one may write: δ∝ = c nº exp(-Ef/kT), where c is a constant. For lead fluoride, a plot of ln(δ∝) versus (l/T) yielded Ef = 0.56 eV which is lower than the literature values. The assumptions in this analysis and the discrepancy in the result are discussed.

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