In order to access this option you should select the EXPERT OPTIONS sheet (close to the upper left corner of the main program window).

Dependent on the target atomic number, on the projectile velocity, and on the required numerical accuracy an optimized quadratic impact-parameter grid is selected, if this option is chosen.

If this option is not checked, the minimum impact parameter **bmin**, the
maximum impact parameter **bmax** (both in units of Å), and the number of
grid points may be selected directly. The impact parameter range should always
stay within 1E-5 ... 100 Å, to avoid numerical problems inside CasP. The selected
number of grid points (n) should be >> 1 (and < 1000), to allow for
the internal impact-parameter integration. The first **b** value is exactly
bmin, the last impact-parameter value is bmax, and n-1 grid points are distributed
in between (quadratic grid). The **Q_e**(b) results for all impact parameters
and for all shells are stored in an output file.