Interference effects in Stark spectra of weakly autoionising 5dnf states of barium

Abstract

Weakly autoionising 5d nf Rydberg states of barium around n"60 have been studied in the presence of a static electric field. The experiment has been carried out in a CW laser-atomic-beam setup. In between the overlapping n"60 and 61 angular momentum manifolds broad 5d63d resonances interact with the manifold states resulting in pronounced interferences. These interferences (anti-crossings) have been analysed by a direct diagonalisation procedure neglecting interactions with the continuum, and by a Multichannel Quantum Defect Theory (MQDT) analysis including continuum interactions.

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

“…The Stark effect on Rydberg states has been the subject of a number of spectroscopic studies in both atomic and molecular systems [8][9][10][11][12][13][14][15][16][17][18]. Recent interest in molecular systems has been stimulated by the effect of fields on the lifetimes of high Rydberg states as used in ZEKE spectroscopy [19,20].…”

“…19s and 19p) undergo a quadratic Stark shift at low fields, whereas the high-l states undergo a linear shift with the field; the near degeneracy of the high-l states means that a sequence of l = ±1 couplings can occur at very low fields giving rise to complete mixing of the high-l manifold. These Stark manifolds can be observed experimentally, by excitation from a ground or intermediate state, provided there is a significant admixture of low-l character and hence transition probability (see, for example, [8,9,[11][12][13][14][15][16][17][18]). At higher fields the low-l and high-l states merge together and all the levels switch to a linear shift with field, although there may be numerous perturbations as the energy levels undergo avoided crossings at and above the so-called Inglis-Teller field (e.g.…”

Cesium Rydberg-state ionization study by three-dimensional ion-electron correlation: Toward a monochromatic electron source

“…Photoabsorption spectra in electric fields (Stark spectra) have been obtained on Rb [1,2], Na [3,4], He [5][6][7], or Ba [8], featuring observations of unstable levels crossings and interference narrowing effects. However, almost no study on Cs exist [9][10][11][12].…”