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Reading data from tables

So far all input parameters but one have been kept constant. In many cases of practical interest, the situation is different: there is still one "independent" variable, but other parameters may depend implicitely on this parameter. As an example, consider the spectral dependence of the extinction cross section Cext. In this case, lambda is the independent variable (or, equivalently, f, k, or invlambda), but  the real and imaginary parts of the refractive index depend on lambda too (dispersion). The dependence of the complex refractive index on lambda must be deduced from experiments and is given in tabular form.  Example:
  

# refractive index of polycrystalline graphite. 
# see optical database for description 
# wavelength in microns in the range  [0.11, 1.]
#  1. column lambda (in microns)  
#  2. column real part of effective refractive index 
#  3. column imaginary part of effective refractive index
#
 0.11000E+00   0.22682E+01   0.94232E+00
 0.13000E+00   0.18412E+01   0.27214E+00
 0.15000E+00   0.14710E+01   0.25562E+00
 0.17000E+00   0.12016E+01   0.41413E+00
 0.19000E+00   0.10481E+01   0.69816E+00
 0.21000E+00   0.10243E+01   0.10136E+01
 0.21500E+00   0.10307E+01   0.10994E+01
 0.21750E+00   0.10381E+01   0.11426E+01
 0.22000E+00   0.10491E+01   0.11854E+01
 0.22500E+00   0.10759E+01   0.12700E+01
 0.24000E+00   0.12065E+01   0.15425E+01
 0.26000E+00   0.15673E+01   0.17973E+01
 0.30000E+00   0.22310E+01   0.16402E+01
 0.33000E+00   0.23895E+01   0.14357E+01
 0.40000E+00   0.25001E+01   0.12484E+01
 0.55000E+00   0.26095E+01   0.11063E+01
 0.70000E+00   0.26734E+01   0.11399E+01
 0.90000E+00   0.27938E+01   0.12310E+01
 0.11000E+01   0.29149E+01   0.13097E+01
 0.12500E+01   0.29950E+01   0.13607E+01
You may use cut and paste to copy these data into the program's text area. However, the program does not yet know how to interpret the data. In order to change this, you have to make the following settings in the input dialog (click on ):
 

This tells the program that  lambda, ref, and refim are to be read from the table (while d and refmed are being kept constant). Close the dialog. The main window will then look like this:


 
The number fields for the parameters lambda, ref and refim are used to specify the column from which the data are to be read in. Choose 1, 2, 3, for the columns respectively. And set d = 0.01 for demonstration purposes. In the output dialog, choose lambda as the abscissa and Qext as the ordinate. Then click on   to plot   Qext(lambda). This results in the following plot:

This plot shows the well-known UV-feature of graphitic particles. Instead of doing all the work with the input/output dialogs, you can as well edit the text in the text area, inserting the following lines in front of the table: 

d=0.01  refmed = 1.33 
in =  {lambda, ref, refim}
out = {lambda, qext}
# refractive index of polycrystalline graphite. 
# see optical database for description 
# wavelength in microns in the range  [0.11, 1.]
#  1. column lambda (in microns)  
#  2. column real part of effective refractive index 
#  3. column imaginary part of effective refractive index
#
 0.11000E+00   0.22682E+01   0.94232E+00
 0.13000E+00   0.18412E+01   0.27214E+00
 0.15000E+00   0.14710E+01   0.25562E+00
 0.17000E+00   0.12016E+01   0.41413E+00
 0.19000E+00   0.10481E+01   0.69816E+00
 0.21000E+00   0.10243E+01   0.10136E+01
 0.21500E+00   0.10307E+01   0.10994E+01
 0.21750E+00   0.10381E+01   0.11426E+01
 0.22000E+00   0.10491E+01   0.11854E+01
 0.22500E+00   0.10759E+01   0.12700E+01
 0.24000E+00   0.12065E+01   0.15425E+01
 0.26000E+00   0.15673E+01   0.17973E+01
 0.30000E+00   0.22310E+01   0.16402E+01
 0.33000E+00   0.23895E+01   0.14357E+01
 0.40000E+00   0.25001E+01   0.12484E+01
 0.55000E+00   0.26095E+01   0.11063E+01
 0.70000E+00   0.26734E+01   0.11399E+01
 0.90000E+00   0.27938E+01   0.12310E+01
 0.11000E+01   0.29149E+01   0.13097E+01
 0.12500E+01   0.29950E+01   0.13607E+01

Then click on  to read and interpret the data. Clicking on   afterwards will lead to a result indentical to that shown earlier.
 
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