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Thorium Dioxide

Crystal: ThO2

Structure: fluorite

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Cohesive energy:

eV

Lattice parameter:

Å

Density:

g/cm3

 

Stiffness constants: in 1011 dynes/cm2, at room temperature

 

c11: 36.7 (Ref.1) or 29.2 (Ref.2)

c12: 10.6 or 14.3

c44: 7.97 or 7.45

Compressibility (in 1011 dynes/cm2):

Poisson ratio:

 

Debye temperature: 393 K (but better q for O)

Melting temperature: 3300 ° C

Neel temperature: K

 

Phonon spectrum discussed by:

 

Transverse optic phonon T0 (k=0): 279 cm-1 for long IR, or 350±5 cm-1 at 77K. (LST relation) (Ref.3)

Longitude optic phonon L0 (k=0): 567 cm-1 or 465 cm-1, or also 464±1 cm-1 at 300K. (Raman) (Ref.3)

 

Gruneissen constant:

Ratio e*/e:

 

Photoelastic constants:

p11:

p12:

p44:

 

 

Band gap:

direct: 5.8 eV. (Ref.4) (see also Ref.5)

indirect: eV.

 

Gap: eV.

First exciton: eV.

 

Band structure discussed by:

 

Static dielectric constant: 18.9±0.4 (3*105 Hz. at room temperature) (Ref.6)

Optic dielectric constant:4.63 (Ref.4)

Thoria work: 2.5±0.5 eV.

O. Bastiansen, O. Hassel, A. Langseth, Dielectric properties of single crystals of BaTi; Nature 160, 129 (1947)

 

Electron mobility:

Hole mobility:

Polaron coupling constant: a = ( for m*=1 )

 

Effective mass:

conduction band:

valence band:

 

Electron affinity: (in eV., from bottom of conduction band under vacuum)

 

Spin-orbit coupling: (valence band)

 

Cation polarisation: Å-3

Anion polarisation: Å-3

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References:

 

  1. J.B. Wachtman Jr. (1969)

    2.  

  2. 2. M.Ishigame, M. Kojima Second-order Raman spectra of Thorium Dioxides, J. Phys. Soc. Jap. 41, 206 (1976)

    3.  

  3. M. Beaumont, B. Claudel, B. Mentzen, Influence de l'incorporation du Th228 sur les proprietes structurales et electroniques de la Thorine, J. Inorg. Nucl. Chem. 32, 1165 (1970)

    4.  

  4. E.T. Rodine, L. Land Electronic defect structure of single-crystal ThO2 by thermoluminescence, Phys. Rev. B4, 2701 (1976)

    5.  

  5. S.T. Pantelides, D.J. Mickish and A.B. Kunz, Electronic structure and properties of magnesium oxide, Phys.Rev. B10, 5203 (1974)

    6.  

  6. J.D. Axe, G.D. Pettit, Infrared dielectric dispersion and lattice dynamics of UO2 and ThO2, Phys. Rev. 151, 676 (1966)

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