Abstract The experimental study of the relations between |m_l| and field ionization thresho- lds of Stark components in Rydberg states of atomic cesium is reporte The threeexpressions of ionization thresholds of |m_l|=0,1, 2 in atomic cesium are obtainedcompletely from the same experiment.
In this paper, we investigate the Stark effect of ultra-cold 39D cesium Rydberg atoms in low-field. The Stark structure of 39D Rydberg states is calculated numerically. The cold cesium atoms are excited to Rydberg states via two-step process and the Stark spectra are obtained by field-ionization method. The scalar and tenson polarizabilities of 39D cesium Rydberg atoms are measured to be α5/22=62(7) MHz·V-2cm2,α5/20=-146(13) MHz·V-2cm2, α3/22=73(6) MHz·V-2cm2,α3/20=-106(20) MHz·V-2cm2 respectively. The experimental values are in agreement with the theoretical results.
We study the excitation and ionization of cesium Rydberg states in an electric field ($\ensuremath{\approx}\phantom{\rule{0.16em}{0ex}}2200\phantom{\rule{4pt}{0ex}}\mathrm{V}/\mathrm{cm}$) near the classical field-ionization threshold ($\ensuremath{\approx}\ensuremath{-}280\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{\ensuremath{-}1}$ binding energy) by three-dimensional (3D) ion-electron coincidence spectroscopy. Cesium atoms are produced by an effusive oven and excited with lasers to Stark-shifted Rydberg states or directly ionized. Using a double time-of-flight setup we record 3D (X,Y, time of flight) coincidence imaging of electrons and ions. Above-threshold photoionization creates broad images with poor electron-ion spatial correlation. Fast ionizing states produce very good correlations and the images reveal the electric-field map of the ionization region. Slow ionizing states show that the relatively high atomic velocity is detrimental to the correlations. Experimental data are accurately reproduced by detailed Monte Carlo excitation and ionization simulations based on Stark maps obtained with local-frame transformation (LFT) theory. Agreement between our spectroscopic experiment and LFT theory is very good, with better that hundreds of megahertz accuracy. But, on rare particular states, several gigahertz discrepancy is found. This study can be used to select appropriate states for the creation of ion and electron beams with high brightness, good correlation, and low energy dispersion.
We investigate the field ionization spectra of ultracold cesium Rydberg atoms in dc electric field. The ionization thresholds of different electric fields are measured and shift of the ionization threshold relative to field-free ionization threshold is accurately described by (6.06 ± 0.14) F 1/2 , which is in good agreement with the classical saddle-point model for field ionization. We obtain the field-free ionization threshold of cesium (6P 3/2 ) as 19674.89 ± 2.99 cm −1 by fitting experimental data.