Scaled-energy spectroscopy of barium autoionizing Rydberg atoms in an electric field

Abstract

Spectra of Ba autoionizing Rydberg states (n = 60-80) in a varying external electric field, keeping the classical scaled energy ε constant, have been measured. Series converging to the 5d 3/2-as well as to the 5d 5/2-limit have been studied for three values of the scaled energy: ε = −2.94, −2.35 and −1.76, deep in the n-mixing regime around the classical field ionization limit (ε = −2.0). The experiments are interpreted using semiclassical closed-orbit theory by taking the Fourier transform of the experimental spectra. High resolution is obtained using CW laser excitation and large frequency scans. Effects of the large non-hydrogenic core of Ba are investigated by comparing the experimental Fourier spectra with hydrogenic closed-orbit theory for m l = 0-3 incorporating the 5d 2 1 G 4 metastable ground-state wavefunction and assuming only 5d-nf excitation.

Scaled-Energy Spectroscopy of Helium and Barium Rydberg Atoms in External Fields

“…More details may be found in refs. [12,13]. Scaled-energy spectra were recorded for high-n Rydberg states (n=60-80) by overlapping several laser scans.…”

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

“…The electron signal and the transmission peaks of a 750 MHz confocal etalon for calibration purposes were simultaneously stored on a computer which also controlled the frequency scan of the ring dye laser. More detailed information on the experimental setup can be found in [5]. Spectra were taken for n+60.…”

“…Most of these studies concerned the behaviour of bound Rydberg states in external fields. Recently we reported on electric field effects in autoionising series [5].…”

“…angular momentum manifolds appear that are fanning out approximately proportional to the strength of the static electric field applied during the excitation. In several recent papers [3][4][5] results on scaled-energy spectroscopy experiments are reported as well.…”

Closed-orbit recurrences in molecular hydrogen

“…The theoretical basis for the advancement of COT, which describes atomic dynamics utilizing the concepts of trajectory and orbits, occurred earlier with the full development of periodic orbit theory by Gutzwiller in 1971 [3]. During the last decade COT has been modified and applied to nonhydrogenic atoms [4][5][6][7] resulting in very good agreement with many Stark SERS experimental studies including those in sodium [1,8], lithium [9,10], barium [11][12][13], calcium [13], helium [14][15][16][17][18], argon [19,20], and strontium [21]. This is also true for other experiments employing SERS with magnetic fields [22][23][24].…”