                  I X S E C S

      IXSECS calculates integrated cross-sections for elastic scattering,
      electronic and vibrational excitation, and dissociative attachment.
      It takes input data from TMATRX.

      Input files:
        Channel and target data          (on unit LUCHAN)
        T-matrices                       (on unit LUTMT )

      Output files:
        None

      The following PARAMETERs are used to define array dimensions

      MAXERN = 10  maximum number of energy subranges (defined in RSOLVE)
      MAXXCH =200  maximum number of scattering channels
                   

      Namelist input /XSECIN/

        The format of the following is 
       (Name, Type, Dimension, Default, Limits, ! description)
        Unless specified otherwise, the default value applies to all elements
        of array variables.
        

        EMIN     R   1         0.    [0.:MAXE]
           ! minimum required scattering energy (in units as specified by 
             IEUNIT).  MAXE is the maximum energy on the T-matrix file

        EMAX     R   1         MAXE  [0.:MAXE]
           ! maximum required scattering energy (MAXE is the maximum energy
             on the T-matrix file)

        ICFORM   C   1         'U'   ['U'|'F']
           ! format flag for channel dataset, 'F' for formatted, 'U' for
             unformatted

        IEUNIT   I   1          1    [1,2]  
           ! units in which input scattering energies are input
                 1= Ryd, 2= eV

        IPRNT    I   6          0    [0|1]
           ! Debug print switches :
             In each case -1 gives less than the default output and +1
             more than the default
                 (1) =1 Print all input data
                 (2) =1 Print vibrational wavefuction data
                 (3) =1 Debug output in dissociating channels
                 (4)  not used
                 (5) =1 Print R-matrices
                 (6) =1 Print all output data

        ITFORM   C   1         'U'   ['U'|'F']
           ! Formatted/unformatted switch for unit LUTMT

        IWRITE   I   1          6    [1:]        
           ! logical unit for printed output

        IXSN     I    1         1    [1:3]
           ! Units to be used for cross-section output
             1 = bohr**2
             2 = angstrom**2
             3 = pi*bohr**2

        LUCHAN   I   1         10    [1:]        
           ! logical unit for input channel and target datasets

        LUTMT    I   1         12    [1:]
           ! logical unit holding input T-matrices

        LUXSN    I   1          0    [1:]
           ! logical unit for (formatted) output of cross sections

        MAXI     I   1          1    [1:NTARG]
           ! label of highest initial state for which cross-
             sections are required (here NTARG counts both electronic
             and vibrational states)

        MAXF     I   1         NTARG [1:NTARG]
           ! label of highest final state for which cross-sections
             are required (here NTARG counts both electronic and
             vibrational states)

        NAME     C   60                          
           ! title for any output

        NCHSET    I   1          1    [0:]        
           ! set numbers of required channel dataset

        NTSET     I   1          1    [0:]
           ! Set number for input T-matrices 

        NVXPRT    I   1         MAXI  [1:MAXI]
           ! Number of initial states to be explicitly included
             in final tabulation of cross-sections
