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Rubidium Fluoride

Crystal: RbF

Structure: NaCl

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Lattice formation energy:

-7.87 eV

Lattice parameter:

2.82 Å (2.789 at 0K.)

Density:

g/cm3

 

Stiffness constants: in 1011 dynes/cm2, at 0K. (extrapolation)

 

c11: 6.527 (0K. extrapolation) (Ref.1)

c12: 0.952

c44: 1.255

 

Compressibility (in 1011 dynes/cm2): 0.3558 ??

Poisson ratio:

 

Debye temperature: 221 K

Melting temperature: K

 

Phonon spectrum discussed by:

G. Raunio & S. Rolandson, Lattice dynamics of NaCl, KCl, RbCl & RbF, Phys. Rev. B2, 2098 (1970)

 

Transverse optic phonon T0 (k=0): 156 or 163 cm-1

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

 

Gruneissen constant:

Ratio e*/e:

 

Photoelastic constants:

p11:

p12:

p44:

 

 

Band gap:

direct: eV. at K

indirect: eV. at ° K

 

Plasmon energy: eV.

Exciton energy: 9.54 eV. (Ref.2)

Valence band width: 3.1eV.

 

Band structure discussed by:

 

Static dielectric constant: 5.91 or 5.99

Optic dielectric constant: 1.93 or 1.94

 

Electron mobility:

Hole mobility:

Polaron coupling constant: a = 5.7 ( for m*=1 )

Effective mass: conduction band:

valence band:

 

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

-0.1 (Ref.3) whatever this means (sign anomalous). The sign is given in Ref.4. Mott & Gurney give 4.16 eV. (Ref.5)

 

Spin-orbit coupling: ( valence band)

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References:

 

1. C.R. Cleavin, D.O. Pederson and B.J. Marshall, Elastic constants of RbF from 300 to 4.2K, Phys. Rev. B5, 3193 (1972)

 

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

 

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

 

4. R.I. Kovtoune, Interaction resonnante de particules chargees avec une onde cyclotronique, J.de Phys. 32, num.4, 290 (1971)

 

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

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