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Uranium Dioxide
Crystal: UO2
Structure: fluorite
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Lattice formation energy: |
106.7 eV. |
Lattice parameter: |
2.734 Å (2.36 for nn distance) |
Density: |
11.1 g/cm3 |
Stiffness constants: in 1011 dynes/cm2, at room temperature
c11: 39.6
c12: 12.1
c44: 6.41
Compressibility (in 1011 dynes/cm2): 0.47*1012 dynes/cm2 ??
Poisson ratio:
Sound velocities:
Vl: ~6.0*105 cm/sec. along cube axes
Vt: ~2.4*105 cm/sec. along cube axes
Debye temperature: 377 K, or 242.16K. for U,
Melting temperature: 3040 ° C
Neel temperature: K
Phonon spectrum discussed by:
Transverse optic phonon T0 (k=0): 280 cm-1
Longitude optic phonon L0 (k=0): 450 cm-1 (Raman)
Gruneissen constant:
Ratio e*/e:
Photoelastic constants:
p11:
p12:
p44:
Band gap: direct: eV.
indirect: eV.
Gap: eV.
First exciton: eV.
Plasmon energy: 19.7 eV.
Difference between conductivity and bonding band: 6eV.
Difference between conductivity and SF: 2.7 eV.
Reference:
B.W. Veal, D.J. Lam, X-ray photoelectronic studies of Thorium, Uranium, and their dioxides, Phys. Rev. B10, 4902 (1974)
UO2 data - Characteristic energy loss:
Bulk plasmon at 23.3 eV.
Surface at 8.9 and 20.5 eV.
Plasmon energy: 19.7 eV.
Polarisability per ion radical: 2.2 Å*exp3 (correction to plasmon energy)
Interband transition: ~3.6 eV.
Ref.: E.A. Bakulin et al.; Characteristic losses of electron energy in UO2; Sov. Phys. Sol. St.16,1670 (1975)
Band structure discussed by:
XPS:
C. Klingshirn, E. Ostertag, R. Levy A new emission line in highly excited ZnO at low temperature, Sol. St. Comm. 33, 883 (1980)
which gives: p-d gap: 5 eV; Localised 5F electrons
Coulomb correlation energy: 4.6 eV.
Static dielectric constant: 24.0
Optic dielectric constant: 5.3
Electron mobility:
Hole mobility:
Polaron coupling constant:
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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Other information:
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