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Lithium Bromide

 

Crystal: LiBr

Structure: NaCl

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Lattice formation energy:

-8.23 eV.

Lattice parameter:

2.74 Å (2.73 at 0K.)

Density: g/cm3

 

 

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

 

c11: 3.959 or 4.721 (Ref.1)

c12: 1.909 or 1.590

c44: 1.909 or 2.052

 

Compressibility (in 1011 dynes/cm2): 0.385 ??

Poisson ratio:

 

Debye temperature: 242-257 K (see Ref.2)

Melting temperature: K

 

Phonon spectrum discussed by:

 

Transverse optic phonon T0 (k=0): 159 or 187 cm-1

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

 

Gruneissen constant:

Ratio e*/e:

 

Photoelastic constants:

p11:

p12:

p44:

 

Electronic band structure of the alkali halides. II: Critical survey of theoretical calculation, R.T. Poole, J. Liesegang, R.C.G. Leckey & J.G. Jenkin, Phys.Rev. B12, 5194 (1975) give:

Valence band width: 4.8 eV.

Gap: 7.6 eV.

Electron affinity: 0.2 eV.

 

Band gap:

direct: eV. at K

indirect: eV. at ° K

 

Plasmon energy:

Exciton energy: 7.23 eV. (Ref.3)

 

Band structure discussed by:

A.B. Kunz, Self-consistant local orbitals for Lithium Halide Crystals, Phys.Rev. B2, 2224 (1970)

 

Static dielectric constant: 12.1 or 13.2 (11.95 at 0K.)

Optic dielectric constant: 3.16 or 3.2 (3.22 at 0K.)

 

Electron mobility:

Hole mobility:

Polaron coupling constant: a = 3.5 ( for m*=1 )

Effective mass: conduction band:

valence band:

 

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

3.52 (by Mott-Gurney, probably 3eV. too high) (Ref.4

 

Spin-orbit coupling: 0.52 ( valence band) (Ref.5)

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References:

 

  1. A. Rastogi, J. Hawranek & R. Lowndes, Lattice dynamics & harmonic self-energies for the Lithium halides Phys.Rev. B9, 1938 (1974)

    2.  

  2. L.S. Ching, J.Day, A.L. Ruoff, Pressure & temperature dependence of the elastic constants of LiBr & LiCl J.Appl.Phys. 44, 1017 (1973)

    3.  

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

    4.  

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

    5.  

  5. J.E. Eby, K.J. Teegarden & D.B. Dutton, Ultraviolet absorption of alkali halides Phys.Rev. 116, 1099 (1959)

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