By default, the numerical step sizes are 0.01 bohr for distances or Cartesian coordinates, and 1 degree for angles. These defaults can be changed using
where dr is the displacement for distances (or Cartesian coordinates) in bohr, and da is the displacement for angles in degree. The value of RSTEP is used for symmetrical displacements. The step sizes for individual variables can be modified using
where the value must be in atomic units for distances and in degree for angles.