c2v,        xsec
 -2.0, 0.010611109
-1.75, 0.008957551
 -1.5, 0.007448759
-1.25, 0.006084734
 -1.0, 0.004865472
-0.75, 0.003790976
 -0.5, 0.002861244
-0.25, 0.002076278
  0.0, 0.001436076
  0.1, 0.001220529
  0.2, 0.001028145
  0.3, 0.000858923
  0.4, 0.000712864
  0.5, 0.000589967
  0.6, 0.000490233
  0.7, 0.000413660
  0.8, 0.000360251
  0.9, 0.000330003
  1.0, 0.000322918
  1.1, 0.000338996
  1.2, 0.000378236
  1.3, 0.000440638
  1.4, 0.000526202
  1.5, 0.000634929
  1.6, 0.000766819
  1.7, 0.000921870
  1.8, 0.001100085
  1.9, 0.001301461
  2.0, 0.001526000
 2.25, 0.002188683
  2.5, 0.002996131
 2.75, 0.003948343
  3.0, 0.005045320
 3.25, 0.006287063
  3.5, 0.007673570
 3.75, 0.009204842
  4.0, 0.010880880