Observation of the Stark effect in autoionizing Rydberg states of Ar with a multichannel quantum-defect analysis

Fielding, HH; Softley, T. P.

doi:10.1088/0953-4075/25/20/010

Cited by 33 publications

(27 citation statements)

References 19 publications

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“…(12) is obtained by employing the relations in Eqs. (10) and (21). Then the quantity J ℓℓ ′ reads where U 0 αℓm (ǫ) (with α = β F or β) denotes the shortrange local frame transformation amplitudes that omit effects of the Stark barrier (see Eq.…”

Section: B Evaluating Of M ℓℓ ′ Matrix Elementsmentioning

confidence: 99%

“…In particular, Fano [1] and Harmin [2] employed the LFT to describe Stark photoabsorption spectra of alkali metal atoms. [2][3][4] The Stark effect of more complex systems could also be treated by the combination of the LFT with multichannel quantum defect theory (MQDT) [5], such as Rydberg atoms with two valence electrons [6][7][8], noble gases [9,10], and even molecular hydrogen [11].…”

Section: Introductionmentioning

confidence: 99%

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Generalized local-frame-transformation theory for excited species in external fields

2016

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A rigorous theoretical framework is developed for a generalized local frame transformation theory (GLFT). The GLFT is applicable to the following systems: to Rydberg atoms or molecules in an electric field, or to negative ions in any combination of electric and/or magnetic fields. A first test application to the photoionization spectra of Rydberg atoms in an external electric field demonstrates dramatic improvement over the first version of the local frame transformation theory developed initially by Fano and Harmin. This revised GLFT theory yields non-trivial corrections because it now includes the full on-shell Hilbert space without adopting the truncations in the original theory. Comparisons of the semi-analytical GLFT Stark spectra with ab initio numerical simulations yields errors in the range of a few tens of MHz, an improvement over the original FanoHarmin theory whose errors are 10-100 times larger. Our analysis provides a systematic pathway to precisely describe the corresponding photoabsorption spectra that should be accurate enough to meet most modern experimental standards.

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Section: B Evaluating Of M ℓℓ ′ Matrix Elementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Generalized local-frame-transformation theory for excited species in external fields

2016

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“…Here, l, K, and J are the azimuthal, the electronic and the total electronic angular momentum quantum numbers, respectively. Two coupling ranges are distinguished according to the strength of the reduced electric field F(n, pЈ)ϭ(F/V cm Ϫ1 ͒n 5 / 3.4ϫ10 9 [␦(pЈ)͑mod1͔͒. Range ͑A͒; The onset of the effective coupling of the doorway and escape states, i.e., 0.7рF(n,pЈ)р2.…”

Section: Bixon and Joshua Jortnermentioning

confidence: 99%

“…Such microsystems are of considerable interest in the context of the determination of fundamental physical constants, 1 the manifestation of long-range Casimir retardation forces, which are revealed on the distance scale of rϾ137 a 0 , 2 the properties of planetary atoms, 3 the spectra of bound states 4 -7 and of autoionizing states 8,9 in external electric 4 -9 and magnetic 10 fields, and the exhibition of huge cross sections ϳa 0 2 n 4 for chemical reactions such as charge exchange. 11 The dynamics of Rydbergs of atoms, diatomic molecules and large molecules is fascinating.…”

Section: Introductionmentioning

confidence: 99%

“…4 -10 Experimental and theoretical studies 4 -7,10 of electric field mixing within nonreactive atomic Rydbergs provided a detailed picture of their Stark maps. In the context of energy-resolved observables for reactive atomic Rydbergs, 8,9 impressive experimental 8,9 and theoretical 8,9 progress was made ͑using the Fano line shape formalism 13 and the quantum defect method 49 ͒ towards the understanding of the Stark absorption lineshapes of the autoionizing Rydbergs of Xe ͑8͒ and of Ar ͑9͒ . These line shapes 8,9 provide information on the autoionization dynamics of (nϭ10 -20) atomic Rydbergs in an electric field.…”

Section: Introductionmentioning

confidence: 99%

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The dynamics of high autoionizing Rydberg states of Ar

Bixon

Jortner

1995

The Journal of Chemical Physics

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In this paper we present a theoretical study of the autoionization dynamics of high 2 P 1/2 npЈ͓3/2͔ 1 Rydbergs ͑with the principal quantum numbers nϭ100 -280͒ of Ar in weak homogeneous electric fields ͑Fϭ0.01 -1.0 V/cm͒, which were experimentally interrogated by time-resolved zero-electron kinetic energy ͑ZEKE͒ spectroscopy ͓M. Mühlpfordt and U. Even, J. Chem. Phys. 103, 4427 ͑1995͔͒, and which exhibit a marked dilution ͑i.e., ϳ2 orders of magnitude lengthening͒ of the lifetimes relative to those inferred on the basis of the n 3 scaling law for the spectral linewidths of the npЈ (nϭ12 -24) Rydbergs. The multichannel effective Hamiltonian ͑H eff ͒ with several doorway state͑s͒ ͑for excitation and decay͒ and pure escape states ͑for decay͒ was advanced and utilized to treat the dynamics of the mixed Stark manifold of the ZEKE Rydbergs. H eff of dimension 2nϪ1 is then constructed for a n Rydberg manifold using independent experimental information on the ͑l dependent͒ quantum defects ␦(l) and the ͑l, K, J dependent͒ decay widths, which are of the form ⌫ 0 (lKJ)/"nϪ␦(l͒… 3 , with ⌫ 0 (lKJ) being the decay widths constants. Here, l, K, and J are the azimuthal, the electronic and the total electronic angular momentum quantum numbers, respectively. Two coupling ranges are distinguished according to the strength of the reduced electric field F(n, pЈ)ϭ(F/V cm Ϫ1 ͒n 5 / 3.4ϫ10 9 [␦(pЈ)͑mod1͔͒. Range ͑A͒; The onset of the effective coupling of the doorway and escape states, i.e., 0.7рF(n,pЈ)р2. Range ͑B͒; The strong mixing domain F(n, pЈ)у3. The lifetimes in range ͑B͒ can be well represented by a nearly democratic mixing of all the doorway and escape states (lKJ), with the average valueIn range ͑B͒ ͗(n)͘ increases with increasing n and is only weakly F dependent. Range ͑A͒ is characterized by a hierarchy of two time scales for the decay, with a short decay component, which manifests the residue of the doorway state, and a distribution of very long lifetimes with an average value ͗ LONG (n)͘Ӎ(n)͗ SM (n)͘, where (n)Ӎ2 -5. In range ͑A͒, ͗ LONG (n)͘ decreases with increasing n and decreases with increasing F, manifesting the enhancement of mixing. We identified range ͑B͒ for nϭ150 -280, where a semiquantitative agreement between the experimental ZEKE lifetimes and spectra and our theory was obtained. A tentative identification of range ͑A͒ for lower n ͑ϭ100-150͒ values was accomplished. We have also performed a theoretical study of the Ar autoionization dynamics via the 2 P 1/2 ndЈ͓3/2͔ 1 doorway state, which was experimentally studied by Merkt ͓J. Chem. Phys. 100, 2623 ͑1994͔͒. The onset of range ͑A͒ was identified in the region nϭ70 -80, with the estimated lifetimes near the onset being in agreement with experiment. Our analysis explains the higher n onset for the npЈ doorway state mixing ͑nӍ100 and FӍ0.1 V/cm͒ than for the npЈ doorway state mixing ͑nЈϭ70 -80 for FӍ0.1 V/cm͒. Experimental values of ͗ LONG (n)͘ ͑around nӍ90͒ in range ͑A͒, excited via the 2 P 1/2 ndЈ͓3/2͔ 1 doorway state, are considerably longer than those predi...

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