_____________________________________________________________________
Lithium Fluoride
Crystal:
LiFStructure: NaCl
_____________________________________________________________________
Lattice formation energy: |
-10.51 eV. |
Lattice parameter: |
2.008 Å at room temperature |
|
(1.996 at 0K.) |
Density: |
2.646 g/cm3 |
Stiffness constants: in 1011 dynes/cm2, at room temperature
c11: 11.12 (12.46 at 0K.) (Ref. 1 & 2)
c12: 6.28 (6.49 at 0K.)
c44: 4.20 (4.24 at 0K.)
Compressibility (in 1011 dynes/cm2): 0.126 ??
Debye temperature: 735 K
Melting temperature: 1143 K
Phonon spectrum discussed by:
G. Dollings, H. G. Smith, R.M. Nicklow, R. Vigayaraghavan, M. K. Wilkinson, Lattice dynamics of Lithium Fluoride, Phys Rev. 168, 970 (1968)
Transverse optic phonon T0 (k=0): 307 or 318 cm-1
Longitude optic phonon L0 (k=0): 660 cm-1 (LST)
Gruneissen constant:
Ratio e*/e: 0.87
Photoelastic constants:
p11:
p12:
p44:
Band gap:
direct: eV. at K
indirect: eV. at ° K
Plasmon energy: 25 eV.
Exciton energy: 13.5 eV. (Ref.4) or 12.9 eV. (Ref.5)
Valence band: 6.1 eV. wide
Band structure discussed by:
A.B. Kunz, Self-consistant local orbitals for Lithium Halide Crystal, Phys Rev. B2, 2224 (1969)
See also Phys Rev. B13, 5540 (1976) for experiments
Static dielectric constant:
9.27 or 8.90 (Ref.6),
8.50 at 0K., 9.073 at 295K.(Ref.6),
8.547 at 15K. (Ref.6)
Optic dielectric constant: 1.92 or 1.90 (Ref.6), 1.93 at 0K.
See also Ref. 7 for T, P dependence
Electron mobility:
Hole mobility:
Polaron coupling constant:
Effective mass: conduction band:
valence band:
Electron affinity: ( in eV., from bottom of conduction band under vacuum)
1.8 eV. from colloid work (Jap.in)
4.12 eV. (Mott-Gurney, Ref.8), probably 3eV. too high
-1.8 eV. (Ping)
Spin-orbit coupling: ( valence band)
_____________________________________________________________________
Other information:
R.A. Verral, R.J. Fields and M.F. Ashby, Deformation-mechanism maps for LiF and NaCl, J. Am. Ceram. Soc. 60, 211 (1977)
_____________________________________________________________________
References:
____________________________________________________________________