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Sodium Fluoride

Crystal: NaF

Structure: NaCl

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Mechanical and structural properties:

Lattice formation energy:	-9.30 eV
Lattice parameter:	2.31 Å (2.295 at 0K.)
Density:	2.851 g/cm³ at 4K

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

c₁₁: 9.630, 10.85 at 4K. (Ref.1) or 10.785 (Ref.2)

c₁₂: 2.459, 2.270 at 4K. or 2.287

c₄₄: 2.794, 2.889 at 4K. or 2.871

See also Other Information

Compressibility (in 10¹¹ dynes/cm²): 0.206 ??

Poisson ratio:

Debye temperature: 491 K

Melting temperature: K

Phonon spectrum discussed by:

W.J.L. Buyers, Lattice dynamics of Sodium Fluoride Phys. Rev. 153, 923 (1967)

Transverse optic phonon T0 (k=0): 239 or 262 cm^-1

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

Gruneissen constant:

Ratio e*/e: 0.93

Photoelastic constants:

p₁₁:

p₁₂:

p₄₄:

Electronic properties:

Band gap:

direct: eV. at K

indirect: eV. at ° K

Plasmon energy: 20.7 eV. (Ref.3)

Exciton energy: 11.2 eV. (Ref.3) or 10.66 (Ref.4)

Valence band width: 4.9 eV.

Band structure discussed by: Kunz, see his work between 1967 & 1968

Static dielectric constant: 6.0 or 4.73

Optic dielectric constant: 1.74 or 1.75

Electron mobility:

Hole mobility:

Polaron coupling constant: a = 5.9 ( for m*=1 )

Effective mass: conduction band:

valence band:

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

4.19, by Mott-Gurney, probably 3eV. too high (Ref.5)

Spin-orbit coupling: ( valence band)

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Other information:

High pressure phase: New high pressure polymorphs Sodium halides, T. Yagi, T. Suzuri & S.I. Akimoto, J. Phys. Chem. Solids 44, 135 (1983)

The high temperature elastic moduli of alkali halides, S. Hart, J. Phys. D10, Letter261 (1977)

Electron density in Sodium Fluoride by Gamma-ray diffractometry, D. R. Yoder & R. Coletta, Phys. Rev. B25, 2545 (1982)

Interatomic Auger transitions in ionic compounds, H. Citrin, J.E. Rowe & S.B. Christman, Phys. Rev. B14, 2643 (1976)

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References:

J.T. Lewis, A. Lehoczky & C.V. Briscoe, Elastic constants of the Alkali Halides at 4.2K Phys.Rev. 161, 877 (1967)

L.E.A. Jones, High temperature behaviour of the elastic moduli of LiF & NaF: comparison with MgO & CaO Phys. Earth & Planet. Int. 13, 105 (1976)

Journal de physique et du radium, 28 (1981)

W.B. Fowler, "Physics of Color Centers", New York: Academic Press (1968)

N.F. Mott & R.W. Gurney, "Electronic processes in Ionic crystals", 2nd. Edition (1950)

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