Controlling the motion of hydrogen molecules: design of a two-dipole Rydberg decelerator

Hydrogen molecules are excited by 1 + 1' (VUV + UV) laser excitation to Rydberg states (n = 15-20) in the inhomogeneous field generated by an electrostatic dipole. High-field or low-field seeking Stark states are selected spectroscopically and experience a force either towards or away from the dipole, respectively. Deflection of the molecular beam is observed if the dipole is oriented parallel to the beam direction, whereas acceleration or deceleration is observed for a perpendicular orientation. The measured deflections and acceleration/deceleration are consistent with trajectory simulations based on the known field and Stark map. A two-dipole device is proposed that creates a travelling potential minimum and would enable deceleration of an H-2 beam seeded in argon to a mean velocity of zero. Simulations are presented of its characteristics. (c) 2005 Elsevier B.V. All rights reserved.