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 Purpose: Computes reflection and transmission of a CAP.
 Usage  : reflex [ -o -g -G -b -h -?] 
          [order eta length mass unit_m e1 e2 unit_e] .

Options : 
 -o FILE : The output is written to file FILE.pl rather than to ./reflex.pl
           The string FILE may be a relative or a full path-name.
 -g      : GNUplot comand lines are written to the output file(s).
 -G      : Grid lines are shown.
 -b      : Plot (refl. + transm.) for four eta's.  (eta, 2*eta, 4*eta, 8*eta).
 -d      : Transmission for DVR. (i.e. squared) 
 -h      : Print this help text. 
 -?      : Print this help text. 
The arguments order, eta and length define the CAP.
mass is the (reduced) mass of the particle in unit unit_m.
If no mass-unit is given, au is assumed.
e1 and e2 give the energy range in unit unit_e.
CAP parameters eta and length are in au.
If eta=0 or eta=?, then the program searches for an optimal eta.
If not all arguments are given, the user is prompted for the missing arguments.
Example : reflex -g 3 0.04 1.8 1.5 H-mass 0.3 15 eV 
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