Molecular Physics
Motional dynamics of Rydberg NO molecules in a transmission-line Rydberg-Stark decelerator
Adam Deller, M. H. Rayment, S. D. Hogan
Abstract
The dynamics of nitric oxide (NO) molecules in a cryogenically cooled, transmission-line Rydberg-Stark decelerator have been studied experimentally and through numerical particle trajectory calculations. The molecules, initially travelling in pulsed supersonic beams, were prepared in states with principal quantum number n = 43, in the Rydberg series converging to the N+=2 rotational state of NO+ using the nℓ X+ 1Σ+←A 2Σ+←X 2Π1/2 resonance-enhanced two-colour two-photon excitation scheme. Deceleration from 795 m/s to rest in the laboratory-fixed frame of reference was achieved in a time of ∼250 μs. The observed motional dynamics of the decelerated and trapped Rydberg molecules is in good quantitative agreement with the results of the calculations. The translational temperature of the trapped molecules was determined to be ∼8 K from their rate of expansion after the trap was switched off. These results are of importance in the interpretation of measurements of lifetimes and decay processes of cold electrostatically trapped Rydberg molecules, and in the optimisation of the operation of this type of decelerator for heavier species.