am1 force thermo rot=2
ethane reaction path following
                                                                                
  C    0.000000  0    0.000000  0    0.000000  0    0   0   0
  C    1.522995  1    0.000000  0    0.000000  0    1   0   0
  H    1.112976  1  109.998169  1    0.000000  0    1   2   0
  H    1.112976  1  109.999924  1  239.921570  1    1   2   3
  H    1.112976  1  109.999924  1  120.078430  1    1   2   3
  H    1.112991  1  109.999924  1  180.000000 -1    2   1   3
  H    1.112961  1  109.999924  1   59.923813  1    2   1   3
  H    1.112991  1  109.999924  1  300.077927  1    2   1   3

170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0