7 research outputs found
Ultracold chemical reactions of a single Rydberg atom in a dense gas
Within a dense environment (atoms/cm) at
ultracold temperatures (), a single atom excited to a
Rydberg state acts as a reaction center for surrounding neutral atoms. At these
temperatures almost all neutral atoms within the Rydberg orbit are bound to the
Rydberg core and interact with the Rydberg atom. We have studied the reaction
rate and products for Rb Rydberg states and we mainly observe a
state change of the Rydberg electron to a high orbital angular momentum ,
with the released energy being converted into kinetic energy of the Rydberg
atom. Unexpectedly, the measurements show a threshold behavior at for the inelastic collision time leading to increased lifetimes of the
Rydberg state independent of the densities investigated. Even at very high
densities (), the lifetime of a
Rydberg atom exceeds at compared to
at . In addition, a second observed reaction mechanism,
namely Rb molecule formation, was studied. Both reaction products are
equally probable for but the fraction of Rb created drops to below
10% for .Comment: 13 pages, 13 figure