This program calculates the rigid body motion of a heavy polar molecule in an electric field, by numerically integrating Euler's equations of motion. The quaternion representation of rotations is used. There is no analytic solution for this system and for strong fields the motion is in unstable to chaos. This one requires lots of numeric integrations so it is implemented in C/Python. It uses the ODE integration routines from GSL, and uses mayavi for visualization of the motion.