Extrema in transition energies resulting not in satellites but in dips within spectral lines

Oks, Eugene; Leboucher-Dalimier, E.

doi:10.1103/physreve.62.r3067

Cited by 12 publications

(15 citation statements)

References 11 publications

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“…These peaks are relatively narrow but their shapes, widths and heights vary significantly with the system parameters. Moreover, they disappear at certain values of F µ and F s , for reason that are sketched in Galvez et al (2000); similar explanations are provided by Oks and Uzer (2000) and Ostrovsky and Horsdal-Pedersen (2003).…”

Section: Introductionsupporting

confidence: 61%

“…where j ′ jk is the kth positive zero of J ′ j (x). This critical value of F µ was first derived in a linear quantal approximation, Galvez et al (2000), and later by Oks and Uzer (2000) using a Floquet approximation and by Ostrovsky and Horsdal-Pedersen (2003) using a linear approximation. Recent experiments, Schultz (2003) and Shultz et al (2004), and comparisons with classical calculations suggest that this estimate can be inaccurate by up to 10%.…”

Section: The Resonance Hamiltonianmentioning

confidence: 84%

“…Since the first observations of these resonances three theoretical papers describing the phenomena from different perspectives have been published. Oks and Uzer (2000) use a Floquet analysis to derive zero-order estimates of F (j) s and F (j,k) µ . Robicheaux et al (2002) have solved Schrödinger's equation for this problem using a split-operator method and have made comparisons with the classical and experimental ionisation probabilities for n 0 = 39 across the j = 1 resonance with F µ = 0.144.…”

Section: Discussionmentioning

confidence: 99%

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The effect of parallel static and microwave electric fields on excited hydrogen atoms

Richards

2005

New J. Phys.

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Motivated by recent experiments we analyse the classical dynamics of a hydrogen atom in parallel static and microwave electric fields. Using an appropriate representation and averaging approximations we show that resonant ionisation is controlled by a separatrix, and provide necessary conditions for a dynamical resonance to affect the ionisation probability.The position of the dynamical resonance is computed using a high-order perturbation series, and estimate its radius of convergence. We show that the position of the dynamical resonance does not coincide precisely with the ionisation maxima, and that the field switch-on time can dramatically affect the ionisation signal which, for long switch times, reflects the shape of an incipient homoclinic. Similarly, the resonance ionisation time can reflect the time-scale of the separatrix motion, which is therefore longer than conventional static field Stark ionisation. We explain why these effects should be observed in the quantum dynamics. PACs: 32.80.Rm, 33.40.+f, 34.10.+x, 05.45.Ac, 05.45.Mt

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Section: Introductionsupporting

confidence: 61%

Section: The Resonance Hamiltonianmentioning

confidence: 84%

Section: Discussionmentioning

confidence: 99%

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The effect of parallel static and microwave electric fields on excited hydrogen atoms

Richards

2005

New J. Phys.

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“…A quasi crossing of the TCC terms, by enhancing charge exchange, can result in unusual structures (dips) in the spectral line profile emitted by a Z-ion from a plasma consisting of both Z-and Z′-ions, as was shown theoretically and experimentally [12][13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 89%

Electric field induced crossings of energy terms of a Rydberg quasi molecule enhancing charge exchange and ionization

Kryukov

Oks

2012

Can. J. Phys.

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Charge exchange is one of the most important atomic processes in plasmas. Charge exchange and crossings of corresponding energy levels that enhance charge exchange are strongly connected with problems of energy losses and of diagnostics in high temperature plasmas. Charge exchange was also proposed as an effective mechanism for population inversion in the soft X-ray and vacuum ultraviolet ranges. One of the most fundamental theoretical domains for studying charge exchange is the problem of electron terms in the field of two stationary Coulomb centers (TCC) of charges Z and Z′ separated by a distance R. It presents an intriguing atomic physics: the terms can have crossings and quasi crossings. These intrinsic features of the TCC problem also manifest in different areas of physics, such as plasma spectroscopy: a quasi crossing of the TCC terms, by enhancing charge exchange, can result in an unusual structure (a dip) in the spectral line profile emitted by a Z-ion from a plasma consisting of both Z-and Z′-ions, as was shown theoretically and experimentally. Before the year 2000, the paradigm was that the preceding sophisticated features of the TCC problem and its flourishing applications were inherently quantum phenomena. In 2000, a purely classical description of the crossings of energy terms was presented. In the present paper we study the effect of an electric field (along the internuclear axis) on circular Rydberg states of the TCC system. We provide analytical results for strong fields, as well as numerical results for moderate fields. We show that the electric field has several effects. First, it leads to the appearance of an extra energy term: the fourth classical energy term -in addition to the three classical energy terms at zero field. Second, but more importantly, the electric field creates additional crossings of these energy terms. We show that some of these crossings significantly enhance charge exchange, while other crossings enhance the ionization of the Rydberg quasi molecule. PACS Nos: 32.60.+i, 32.80.Ee, 34.70.+e, 33.80.Be, 31.15.-pRésumé : L'échange de charge est le plus important mécanisme atomique dans les plasmas. L'échange de charge et le croisement des niveaux d'énergie correspondants qui augmente l'échange de charge sont fortement connectés aux problèmes de perte d'énergie et de diagnostique dans les plasmas de haute température. L'échange de charge a aussi été proposé comme un mécanisme efficace pour l'inversion de population dans les domaines VUV et rayon-X mou. Le problème des termes de l'électron dans le champ de deux centres coulombiens stationnaires (TCC) de charges Z et Z′ séparés par une distance R, est central dans l'étude de l'échange de charge. C'est un problème intriguant en physique atomique : les termes peuvent avoir des croisements et des quasi croisements. Ces caractéristiques intrinsèques se manifestent également dans d'autres domaines de la physique, comme la spectroscopie du plasma : un quasi croisement des termes TCC, par augmentation de l'échange de charge, peut donner ...

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“…In spite of successful applications of the elaborated theory to experiments with neutrals, for example, [6][7][8][9], attention had not been paid to ion collisions in plasma, until recent experiments in hot dense plasmas [10][11][12][13][14] exhibiting fine structures, that is, satellites in F Lyman β profile emitted by a fluorine plasma, dips, and bumps in the Al Lyman γ profile emitted by a heterogeneous Al-C plasma. The fine structures in Al Lyman γ have been connected to intersections of QM Al-C energy terms.…”

Section: Introduction: Features Of Spectral Profiles Following the Inmentioning

confidence: 99%

Optical Transitions and Charge-Exchange in Highly Charged Quasi-Molecules

Devdariani

Dalimier

Sauvan

2010

International Journal of Spectroscopy

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The interaction between quasimolecular states produces not only nonadiabatic transitions but also some exotic features in the wings of the spectral profiles emitted by the ions in collision. Although this concept has been fruitfully used for neutral species, some new highlighted experimental data on quasimolecular optical transitions in hot dense plasma have renewed the interest to the concept in the recent years. The present review deals with highly charged quasimolecules and it is dedicated specifically to quasimolecules formed by two bare nuclei and one bound electron. The reason for this choice is that, for such quasimolecules, the energy terms and the dipole moments of the optical transitions can be obtained straightforwardly in nonrelativistic case without any approximation that are typical for neutrals. Although the results obtained in the frame of the approach developed here are directly applicable to the case of single collisions or to low-density plasmas, they form a reasonable initial approximation for the problem of optical profiles in hot dense plasmas and can be regarded as a safe framework for qualitative discussions of profiles in those environments.

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Extrema in transition energies resulting not in satellites but in dips within spectral lines

Cited by 12 publications

References 11 publications

The effect of parallel static and microwave electric fields on excited hydrogen atoms

The effect of parallel static and microwave electric fields on excited hydrogen atoms

Electric field induced crossings of energy terms of a Rydberg quasi molecule enhancing charge exchange and ionization

Optical Transitions and Charge-Exchange in Highly Charged Quasi-Molecules

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