Motion of an electric dipole in a static electromagnetic field

Expressions for the force and torque on a moving electric dipole in a magnetostatic field are combined with those due to an electrostatic field. By sending oriented molecular dipoles into a region of crossed magnetic and electric fields, the molecules are selectively rotated based on the direction and magnitude of their velocities. In principle this field configuration could be used to create a molecular isolator that only lets molecules through in one direction.