def __init__(self, force_constant, i0, i1, i2):
HarmonicEnergyTerm.__init__(self, force_constant, (i0, i1, i2), bend_angle)<EOL>
Arguments:
 | ``force_constant`` -- The force constant in atomic units.
 | ``i0`` -- The atom index of the first atom in the angle.
 | ``i1`` -- The atom index of the central atom in the angle.
 | ``i2`` -- The atom index of the third atom in the angle.