Navigation:  Scatterers > The RT file format

The RT file format used to store average single scattering characteristics is a text file format. Basically it contains one long column of data structured in a way described below. Some details of the file format may appear a little strange - well, it is a quite old format and its history will not be discussed here.

An example of an RT file is shown first:

 

0.0

180.0

  9150

  .94395262E-22   .10000000E+05   .25000000E+05     50   .10000000E+01

 .382960E-19

 .488527E-18

    .597476E-19

    .597382E-19

    .597103E-19

    .596638E-19

    .595988E-19

    .595154E-19

    .594137E-19

    .592939E-19

    .591560E-19

    .590003E-19

    .588269E-19

    .586360E-19

    .584280E-19

    .582030E-19

    .579613E-19

    .577033E-19

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.

 

The individual columns have the following meaning:

 

0.0

Line 1: Minimum angle (should be 0 in all cases)

180.0

Line 2: Maximum angle (should be 180 in all cases)

  9150

Line 3: Total number of data points: This is the product of the number of spectral points and angular points

  .94395262E-22   .10000000E+05   .25000000E+05     50   .10000000E+01

Line 4: This line holds 5 numbers. The first one is the parameter t which is the average volume of the scattering particles. The unit to be used here is m^3. The next three numbers define the spectral range (which must in wavenumbers!): Wavenumber minimum, wavenumber maximum and number of data points. The last number is the refractive index of the host material surrounding the scattering particle.

Dividing the total number of data points (9150) by the number of data points of the spectral range (50) one gets 183. This means that there are 183 numbers for each wavenumber in the file: The cross section for absorption (in m^2), the cross section for scattering (in m^2 as well) and 181 data points covering the angle range from 0 to 180 degrees in 1 degree steps.

Starting with the minimum wavenumber, these 183 data points will now follow. Then the 183 numbers for the next wavenumber point are stored in the file, and so on until all wavenumber points are processed.

 .382960E-19

Line 5: Absorption cross section for 10000 1/cm

 .488527E-18

Line 6: Scattering cross section for 10000 1/cm

    .597476E-19

Line 7: Scattering probability W(0°)

    .597382E-19

Line 8: Scattering probability W(1)

    .597103E-19

Line 9: Scattering probability W(2)

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You can inspect the data stored in RT files using the View_RT utility program that is delivered with SPRAY.