Control of atomic and molecular motion via the Stark effect in Rydberg states

A novel theoretical study of the control of translational motion of atomic and molecular Rydberg states in inhomogeneous static electric fields is pre sented. Simulations have been carried out demonstrating that, under realist ic conditions, the deflection and focusing of Rydberg atoms and molecules s hould be achievable. Advantage is taken of the high susceptibility of the R ydberg states to external electric fields, allowing the use of much smaller fields than would be necessary for ground state neutrals. The simulations presented are for trajectories of Rydberg states with n = 18-20 in the fiel ds of an electric dipole, quadrupole and hexapole. A deflection of 7 mm is predicted for n = 18 Rydberg states travelling parallel to the dipole after 100 mu s time of Eight. In the hexapole n = 20 Rydberg states are refocuse d to a spot size of the order of the laser beam waist (10 mu m) after 20 mu s. It is demonstrated that the hexapole can also act as a cylindrical lens if its axis is perpendicular to the Rydberg beam direction. Spontaneous em ission and black-body decay rates are also calculated, and their variation with the applied field is investigated. The potential applications of this work might include the use of focusing and deflection for controlled low-en ergy collisions of Rydberg molecules with surfaces.