Kelly, J. F. ; Hessler, J. P. ; Alber, G. (1986)
Experimental studies of three-photon ionization of Ba: Evidence of channel interference and Raman coupling.
In: Physical Review A, 33 (6)
doi: 10.1103/PhysRevA.33.3913
Artikel, Bibliographie
Kurzbeschreibung (Abstract)
Three-photon ionization spectra of Ba were studied which result from two-photon resonances between the 6s2 1S0 ground state and the 6snd J=2,6s(n+1)s 1S0 (16≤n<40) Rydberg states and 5d7d 1D2,3P0,2 perturber states. A tunable laser with field strength 10−(4−5) a.u. was used to drive the excitation in a low-density atomic beam (n≲3×108 cm−3). Resonant line shapes were systematically studied as a function of light polarization and intensity. Studies with linearly polarized light find all resonant line shapes manifest the same peak shift and asymmetry which is traced to the ac Stark shift of the ground state. The resonant peak height, shift, and linewidth scale linearly with light intensity which is accounted for with a rate-equation formulation.
For the case of circular polarization, a distinct minimum of ionization occurs between each J=2 doublet of the 6snd series. One level (generally 3D2) is significantly broadened in comparison to the laser linewidth (0.1 cm−1) with increasing intensity while its sister level remains narrow (∼0.2 cm−1). Further, light shifts of the 3D2 states are generally ≳1 cm−1 to the red while shifts of 1D2 states are negligible. This behavior switches for the n=27 doublet. Lastly, the dynamic shifts are not quadratic with the field strength. These effects are attributed in part to cancellation due to channel interference and a two-photon Raman process which mixes each J=2 doublet. These processes act in conjunction with the ac Stark effect to produce the observed profile behavior. The shifts and coupling of the excited states are attributed to the influence of the 6pnd Jπ=3− autoionization series and are shown to be sensitive to the singlet-triplet mixing coefficient β of the J=2 doublets. A perturbation analysis is introduced which accounts for the salient features of the data, although it does not include bandwidth and saturation effects. Calculations of light shifts of the 6snd J=2 levels based on this analysis require β be modified from previous assignments based on hfs measurements for n in the vicinity of the 5d7d 1D2 perturber.
| Typ des Eintrags: | Artikel |
|---|---|
| Erschienen: | 1986 |
| Autor(en): | Kelly, J. F. ; Hessler, J. P. ; Alber, G. |
| Art des Eintrags: | Bibliographie |
| Titel: | Experimental studies of three-photon ionization of Ba: Evidence of channel interference and Raman coupling |
| Sprache: | Englisch |
| Publikationsjahr: | 1 Juni 1986 |
| Verlag: | APS Physics |
| Titel der Zeitschrift, Zeitung oder Schriftenreihe: | Physical Review A |
| Jahrgang/Volume einer Zeitschrift: | 33 |
| (Heft-)Nummer: | 6 |
| DOI: | 10.1103/PhysRevA.33.3913 |
| URL / URN: | https://journals.aps.org/pra/abstract/10.1103/PhysRevA.33.39... |
| Kurzbeschreibung (Abstract): | Three-photon ionization spectra of Ba were studied which result from two-photon resonances between the 6s2 1S0 ground state and the 6snd J=2,6s(n+1)s 1S0 (16≤n<40) Rydberg states and 5d7d 1D2,3P0,2 perturber states. A tunable laser with field strength 10−(4−5) a.u. was used to drive the excitation in a low-density atomic beam (n≲3×108 cm−3). Resonant line shapes were systematically studied as a function of light polarization and intensity. Studies with linearly polarized light find all resonant line shapes manifest the same peak shift and asymmetry which is traced to the ac Stark shift of the ground state. The resonant peak height, shift, and linewidth scale linearly with light intensity which is accounted for with a rate-equation formulation. For the case of circular polarization, a distinct minimum of ionization occurs between each J=2 doublet of the 6snd series. One level (generally 3D2) is significantly broadened in comparison to the laser linewidth (0.1 cm−1) with increasing intensity while its sister level remains narrow (∼0.2 cm−1). Further, light shifts of the 3D2 states are generally ≳1 cm−1 to the red while shifts of 1D2 states are negligible. This behavior switches for the n=27 doublet. Lastly, the dynamic shifts are not quadratic with the field strength. These effects are attributed in part to cancellation due to channel interference and a two-photon Raman process which mixes each J=2 doublet. These processes act in conjunction with the ac Stark effect to produce the observed profile behavior. The shifts and coupling of the excited states are attributed to the influence of the 6pnd Jπ=3− autoionization series and are shown to be sensitive to the singlet-triplet mixing coefficient β of the J=2 doublets. A perturbation analysis is introduced which accounts for the salient features of the data, although it does not include bandwidth and saturation effects. Calculations of light shifts of the 6snd J=2 levels based on this analysis require β be modified from previous assignments based on hfs measurements for n in the vicinity of the 5d7d 1D2 perturber. |
| Fachbereich(e)/-gebiet(e): | 05 Fachbereich Physik 05 Fachbereich Physik > Institut für Angewandte Physik 05 Fachbereich Physik > Institut für Angewandte Physik > Theoretische Quantenphysik |
| Hinterlegungsdatum: | 04 Mai 2022 13:17 |
| Letzte Änderung: | 26 Okt 2022 09:45 |
| PPN: | 50077854X |
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