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The Cosmic Ice Laboratory - IR Spectra

The Cosmic Ice Laboratory - Optical Constants from IR Spectra



Interference Fringes - Free Software

    This Excel file (394 kilobytes) will allow you to fit a set of interference fringes with a method similar to that described by Romanescu et al. (Icarus, 2010). The calculation is not particularly difficult, but we are unaware of a free, open-source computer routine for doing it, and that employs a straightforward graphical user interface. We have tested the file given here and know that it works with Excel and the OpenOffice package. Note that there are instructions in the second and third tabs at the bottom of the spreadsheet.

    If you find this file helpful in your research then please acknowledge any use by reference to "Hudson et al." and this NASA web site. Many variations of this file come to mind, and so we would be glad to have copies of any improvements you make.
Spectral Calculation - Free Software

    This Excel file (4.76 megabytes) will allow you to calculate IR transmission spectra from optical constants, n and k, based on the method of Swanepoel (1983) referenced in the file. The calculation is not particularly difficult, but we are unaware of a free, open-source computer routine for doing it, and using a straightforward graphical user interface. We have tested the file given here and know that it works with Excel and the OpenOffice package.

    If you find this file helpful in your research then please acknowledge any use by reference to "Hudson et al." and this NASA web site. Many variations of this file come to mind, and so we would be glad to have copies of any improvements you make.


Acetone ((CH3)2CO) Ice

    Links to tables of the real (n) and imaginary (k) parts of the complex index of refraction of solid acetone are given below. Note that these two files are in the Excel (xlsx) format.

Region Initial Ice Phase Temperature and Data
3600 - 500 cm-1 Amorphous 10 K
3600 - 500 cm-1 Crystalline 125 K

Methane (CH4) Ice

    A link to a table of the real (n) and imaginary (k) parts of the complex index of refraction, and the transmission spectrum, of methane ice is given below. Note that the amorphous phase will crystallize on warming. -- More methane data will be posted soon.

Region Initial Ice Phase Temperature and Data
5000 - 400 cm-1 Amorphous 10 K - spectra, n, and k

Ethane (C2H6) Ices

    Links to tables of the real (n) and imaginary (k) parts of the complex index of refraction, and transmission spectra, of ethane ices are given below. Note that the amorphous and metastable ices crystallize on warming.

    A copy of the paper describing this work is available here (pdf format).

Region Initial Ice Phase Temperatures (K) and Data
4500 - 500 cm-1 Amorphous 16, 20, 30, 40, 50, 60
  Metastable 11, 20, 30, 40, 50 60
  Crystalline 12, 20, 30, 40, 50, 60

Ethylene (C2H4) Ices

    Links to tables of the real (n) and imaginary (k) parts of the complex index of refraction, and transmission spectra, of ethylene ices are given below. Note that the amorphous and metastable ices crystallize on warming.

    A copy of the paper describing this work is available here (pdf format).

Region Initial Ice Phase Temperatures (K) and Data
5000 - 700 cm-1 Amorphous 12, 20, 30, 40, 50, 60
  Metastable 14, 20, 30, 40, 50, 60
  Crystalline 16, 20, 30, 40, 50, 60

Acetylene (C2H2) Ices

    Links to tables of the real (n) and imaginary (k) parts of the complex index of refraction, and transmission spectra, of acetylene ices are given below. Note that there is overlap in the tables between the mid- and near-IR regions, near 3500 cm-1.

    A copy of the paper describing this work is available here (pdf format).

Region Ice Phase Temperatures (K) Data
Near-IR Amorphous 12, 20, 30, 40, 50, 60, 70 Spectrum       n       k
  Crystalline 15, 20, 30, 40, 50, 60, 70 Spectrum       n       k
Mid-IR Amorphous 12, 20, 30, 40, 50, 60, 70 Spectrum       n       k
  Crystalline 15, 20, 30, 40, 50, 60, 70 Spectrum       n       k

Nitrile Ices

    Links to tables of the real (n) and imaginary (k) parts of the complex index of refraction of nitrile ices are given below. Note that there is overlap in the tables between the mid- and far-IR regions, near 500 cm-1.

    Each table is in the machine-readable format used by The Astrophysical Journal.

    A copy of the paper describing this work is available here (pdf format).

Nitrile
Ice
Ice Phase Temperatures (K) Data
HCN Amorphous 50, 75, 95, 110 n       k
  Crystalline 20, 35, 50, 75, 95, 110, 120 n       k
C2N2 Amorphous 50, 75 n       k
  Crystalline 20, 35, 50, 75, 95 n       k
CH3CN Amorphous 50, 75, 95, 110 n       k
Crystalline 20, 35, 50, 75, 95, 110, 130 n       k
C2H5CN Amorphous 50, 75, 95, 110 n       k
Crystalline 20, 35, 50, 75, 95, 110, 140 n       k
HC3N Amorphous 50, 75, 95 n       k
Crystalline 20, 35, 50, 75, 95, 110 n       k


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