`STEP`

In a reaction path, if the path step is constant, STEP can be used instead of explicitly specifying each point. The number of steps is given by POINT.

The STEP size is under user control. Use a value that will allow the potential energy surface to be drawn without having it look too jerky. For the CH₃CL stretch example below, the step-size was 0.02 Ångstroms. This gives a nice PES. If a smaller step-size is used, it should still run okay, but the run will take longer, because the number of points needed will be larger.

Example: Stretching a C-Cl bond in CH₃Cl. In this example, the C-Cl bond length starts at 1.5 Ångstroms, and stretches by 0.02 Ångstroms at a time to 2.3 Ångstroms.

   step=0.02  point=40 
 CH3Cl Stretching the C-Cl bond

 Cl    0.00000000  0    0.0000000  0    0.0000000  0    0    0    0     
  C    1.50000000 -1    0.0000000  0    0.0000000  0    1    0    0      
  H    1.10153604  1  108.0234648  1    0.0000000  0    2    1    0      
  H    1.10231454  1  108.0092176  1  120.0000000  1    2    1    3      
  H    1.10177640  1  107.8415102  1 -120.0000000  1    2    1    3

For an alternative way of defining points on a path, that produces an output similar to the conventional output, see alternative points.