Applications of molecular Rydberg states in chemical dynamics and spectroscopy

Rydberg-Stark deceleration of atoms and molecules

“…The corresponding fluorescence lifetimes of the shortest-lived lowstates typically exceed 1 µs for values of n > 30. In molecules low-Rydberg states often predissociate on timescales 1 µs before spontaneous emission can occur [2,3]. However, for molecules with a stable ion core, provided the Rydberg electron possesses sufficient orbital angular momentum (typically if ≥ 4) predissociation cannot occur directly, and long-lived states with characteristic properties similar to those of Rydberg states in the H atom result.…”

“…The interactions of atoms and molecules in high Rydberg states with surfaces are of importance in several areas of research, including, e.g., cavity-quantumelectrodynamics at vacuum-solid-state interfaces [39,48], experiments involving the photoexcitation of Rydberg states of samples confined in miniature vapor cells [49], and studies of charge transfer [3,50]. At distances of < 10 µm from conducting surfaces, the interaction of a Rydberg atom or molecule with its image-dipole in the surface contributes to state-changing and attractive forces toward the surface [48,51,52].…”

“…This involves the transfer of energy from the Rydberg electron to the nuclear degrees of freedom of the molecule, typically as a result of the interaction between the potential energy surface of the Rydberg state with that of a repulsive valence state. The outcome of this process is the decay of the molecule into two or more fragments in their ground or excited states [2,3].…”

High-field-seeking Rydberg atoms orbiting a charged wire

“…These include (i) collision and spectroscopic studies involving low angular momentum Rydberg states in which the Rydberg electron couples strongly to the ion core [15], (ii) the confinement and manipulation of antihydrogen atoms which are produced simultaneously in low-and high-fieldseeking Rydberg-Stark states [16,17], and (iii) approaches to hybrid cavity-quantum electrodynamics involving atoms in high angular momentum circular Rydberg states which are always high-field seeking and exhibit quadratic Stark energy shifts [18][19][20]. With applications in these areas in mind, we report the results of experiments in which beams of helium (He) atoms in the triplet high-field-seeking 52p Rydberg state have been guided while following helical trajectories in the electrostatic field of a charged wire suspended along the axis of a grounded cylindrical metallic tube.…”

Single-color two-photon spectroscopy of Rydberg states in electric fields

“…The magnitude of these dipole moments scale with n 2 , and at n = 30 can exceed 3000 D. In addition to the importance of the results presented here for Doppler-free Rydberg state photoexcitation, when driven using circularly polarized laser radiation such multiphoton excitation schemes represent a general approach to the preparation of long-lived non-core-penetrating Rydberg states of small molecules. With their small quantum defects, and long fluorescence lifetimes, these states are ideally suited for deceleration and electric trapping experiments [18,19], directed toward studies of excited state decay processes, and low energy scattering with other gas-phase targets, or surfaces [20].…”