Optical Data of Cosmic Dust Analogues

Laboratory Astrophysics Group of the AIU Jena

Additional information about synthetic fayalite:

A synthetic fayalite crystal from the group of Prof. Assmuss (University of Frankfurt (Main)) grown by the scull method was spectroscopically investigated .
  • The scull provided small (up to 4 mm sized) nearly black fayalite single fayalite crystals. Two crystals have been crystallographically oriented by the Laue diffraction method. Their chemical compositions were checked by energy dispersive X-ray analysis (EDX) at a SEM to Mg1.9Fe0.1SiO4.
  • The optical constants were obtained by oscillator fit analysis to the reflection spectra.
  • Reflection spectra and lattice modes

  • Reflection spectra of synthetic fayalite E||x (ASCII)

  • Reflection spectra of synthetic fayalite E||y (ASCII)

  • Reflection spectra of synthetic fayalite E||z (ASCII)

    By doing oscillator fit analysis, the optical constants have been derived (E||x):

    (E||y):

    (E||z):

  • Fayalite E || x (ASCII)
  • Fayalite E || y (ASCII)
  • Fayalite E || z (ASCII)

    Using these data, IR absorption spectra of fayalite particles have been calculated:
    1) spheres
    2) a continuous distribution of ellipsoids, where all shapes are equally probable (CDE1)
    3) a distribution of ellipsoid with a quadrativ weighting, where near spherical shapes are most probable (CDE2).
    The calculations have been performed for small particles in the Rayleigh limit.

  • Mass absorption coefficients of fayalite spheres, CDE1 and CDE2 in vacuum (ASCII).
  • Mass absorption coefficients of fayalite powder (d < 1 micron, ground single crystals) by using the PE/KBr pellet technique (ASCII).



  • Additionally, optical constants of fayalite are available from the Ultraviolet to the NIR. The data have been obtained from unpolarized measured reflection and transmission spectra of thin sections.
  • Optical constants of fayalite from 25000 to 1000 cm-1 (ASCII)

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        Last modified: Dirk Fabian, January 2002