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Potassium Bromide

 

Crystal: KBr

Structure: NaCl

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Lattice formation energy:

-6.87 eV.

Lattice parameter:

3.30 Å (3.262 at 0K.)

Density:

2.75 g/cm3

 

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

 

c11: 3.46 or 4.17

c12: 0.58 or 0.52

c44: 0.505 or 0.52

Compressibility (in 1011 dynes/cm2): 0.649 ??

 

Poisson ratio:

 

Debye temperature: 172 K

Melting temperature: K

 

Phonon spectrum discussed by:

A.D.B Woods, W. Cochran & B.N. Brockhouse, Lattice dynamics of alkali halide crystals, Phys.Rev. 119, 980 (1960)

Also: A.D.B.Woods,B.N. Brockhouse & R.A. Cowley Lattice dynamics of alkali halide crystals.II: Studies of KBr & NaI, Phys. Rev. 131, 1025 (1963)

 

Transverse optic phonon T0 (k=0): 101 or 123 cm-1

Longitude optic phonon L0 (k=0): 166 cm-1 (Hodby)

 

Gruneissen constant:

Ratio e*/e: 0.76

 

Photoelastic constants:

p11:

p12:

p44:

 

 

Band gap: direct: eV. at K

indirect: eV. at ° K

Plasmon energy: 13.3 eV. (Ref.1)

Exciton energy: 7.6 eV. (Ref.1) or 6.71 (Ref.2)

 

Band structure discussed by:

 

Static dielectric constant: 4.78 or 4.52 (Hodby)

Optic dielectric constant: 2.33 or 2.39 (Hodby)

Also for more information: Newton scattering investigation of the acoustic-mode Gruneinsen parameters in RbBr, G. Ernst, G. Krexner & G. Quittner, Phys.Rev. B29, 5805 (1984)

 

Electron mobility:

Hole mobility:

Polaron coupling constant:

a = 3.52 ( for m*=1 )

a = 3.07 or 3.15 (Hodby)

 

Effective mass:

conduction band:

0.428 (band mass)

 

0.367 or 0.388 (Hodby)

polaron:

0.700 (Hodby)

valence band:

 

 

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

0.6 eV.(Ref.3) also: 0.9 eV. (Ref.4)

Mott-Gurney estimate 3.52 eV. (Ref.5)

Jap.in estimates 0.36 eV. from colloids

 

Spin-orbit coupling:

0.49 ( valence band) (Ref.6)

( for all bromides, see Ref.7)

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Other information:

 

 

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References:

 

  1. Journal de Physique et le Radium, 28 (1981)

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

  3. M.N. Pisanias & W.H. Hamill, Anomalous high-field electron injection & photoconduction in thin-film alkali halides, J. Appl. Phys. 51, 1569 (1980)

  4. T. Sasaki, Y. Iguchi & H. Sugawara, Photoelectric emission of Potassium halides in the extreme ultraviolet, J. Phys. Soc. Jap. 30, 580 (1971)

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

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

  7. G. Guizetti, L. Nosenzo & E. Reguzzoni., Optical properties & electronic structure of alkali halides by thermoreflectivity, Phys.Rev. B15, 5921 (1977)

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