Ultracold molecular collisions in combined electric and magnetic fields

We consider collisions of electric and magnetic polar molecules, taking the OH radical as an example, subject to combined electric and magnetic static fields. We show that the relative orientation of the fields has an important effect on the collision processes for different fields' magnitudes at different collision energies. This is due to the way the molecules polarize in the combined electric and magnetic fields and hence the way the electric dipole-dipole interaction rises. If OH molecules are confined in magnetic quadrupole traps and if an electric field is applied, molecular collisions will strongly depend on the position as well as the velocity of the molecules. Consequences on the molecular dynamics are discussed.