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Barium Oxide

Crystal: BaO

Structure: NaCl

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Mechanical and structural properties:

Lattice parameter:	2.76 Å
Density:	g/cm³

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

c₁₁: See Ref. 1, 2

c₁₂:

c₄₄:

Compressibility (in 10¹¹ dynes/cm²):

Poisson ratio:

Debye temperature: 272 K

Melting temperature: 1380 ° C (sublimes) 1928 or 1917

Phonon spectrum discussed by: see J. Phys. Chem. Soc. July/Aug. 1975

Transverse optic phonon T0 (k=0): Parodi cites 189 cm^-1 IR abs.

Longitude optic phonon L0 (k=0): cm^-1

Gruneissen constant:

Ratio e*/e:

Photoelastic constants:

p₁₁:

p₁₂:

p₄₄:

Electronic properties:

Band gap: direct: 4.0 or 4.8 eV (Henderson & Hughes) or 3.95 (Bessent)

First exciton: 4.06 eV. (Ref.3)

Valence band width: 8.4 eV

(Mott-Gurney,"Electronic processes in Ionic crystals", 2nd. Edition (1950))

Band structure discussed by:

Static dielectric constant: 34 (NOT 14.4)

Optic dielectric constant: 3.83

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)

0.5 (Ref.4) or 0.57 (Ref.5)

Spin-orbit coupling: ( valence band)

Cation polarisation: 1.550 Å^-3

Anion polarisation: 3.050 Å^-3

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References:

1. V.H. Vetter, R.A. Bartels BaO single crystal elastic constants and their temperature dependence, J. Phys. Chem.S ol. 34, 1448 (1973)

2. Z. Chang, E.K. Graham Elastic properties of oxides in the NaCl-Structure, J. Phys. Chem. Soc. 38, 1355 (1977)

3. B. Ulrici, W. Ulrici, N.N. Kovalev Optical absorption in SrO single crystals, Sov. Phys. Sol. St. 17, 2305 (1976)

4. S. 60, 13 (1948)

5. K.Y. Tsou and E.B. Hensley Electron affinities of the alkaline earth chalcogenides, J. Appl. Phys. 45, 47 (1974)

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