Angular potential

The 3-body angular potential requires in.params.angular file of the following format.

# type,   cspi, cspj, cspk,  rc3,   alp,   bet,   gmm
 1   Zr    O     O      3.50    2.133   1.000  -0.677
 1   P     O     O      3.50    2.282   1.000  -0.553

• Lines starting with # or ! are treated as comments.
• The first entry is the type of the angular potential to be among species specified in the following entry.