Stern-Gerlach deflection of field-free aligned paramagnetic molecules.

The effects of laser-induced pre-alignment on the deflection of paramagnetic molecules by inhomogeneous static magnetic field are studied. Depending on the relevant Hund's coupling case of the molecule, two different effects were identified: either suppression of the deflection by laser pulses (Hund's coupling case (a) molecules, such as ClO), or a dramatic reconstruction of the broad distribution of the scattering angles into several narrow peaks (for Hund's coupling case (b) molecules, such as O(2) or NH). These findings are important for various applications using molecular guiding, focusing and trapping with the help of magnetic fields.