Molecular Applications of Quantum Defect Theory

Greene, Chris H.; Jungen, Ch.

doi:10.1016/s0065-2199(08)60141-4

Cited by 468 publications

(279 citation statements)

References 137 publications

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“…(22) indicates that two infinite summations must be performed. Actually, the difference of the two sums in Eq.…”

Section: B Evaluating Of M ℓℓ ′ Matrix Elementsmentioning

confidence: 99%

“…Actually, the difference of the two sums in Eq. (22) ensures that the left hand side remains finite. Note that the first sum arises from the Coulomb-Stark Hamiltonian whereas the second term emerges from the Coulombic one.…”

Section: B Evaluating Of M ℓℓ ′ Matrix Elementsmentioning

confidence: 99%

“…In molecular applications frame transformation theory has been decisive in describing the rich rovibrational Rydberg spectra of diatomic molecules [22], and the dissociative recombination of H + 3 [23,24]. Despite the versatile landscape of physical applications and the successes of the LFT theory, it lacks one important attribute for a comprehensive theory: there is no systematic pathway for improving the accuracy of the method.…”

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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“…(22) indicates that two infinite summations must be performed. Actually, the difference of the two sums in Eq.…”

Section: B Evaluating Of M ℓℓ ′ Matrix Elementsmentioning

confidence: 99%

Section: B Evaluating Of M ℓℓ ′ Matrix Elementsmentioning

confidence: 99%

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 system of equations similar to (9), but homogeneous, was analyzed by Giusti-Suzor and Zoller [39] from the point of view of multichannel quantum defect theory (MQDT) [41,42]. For analysis of the threshold behavior we use a somewhat different, but equivalent, R-matrix method.…”

Section: Near-threshold Behavior Of Multiphoton Ionization Ratesmentioning

confidence: 99%

Threshold effects in strong-field ionization: Energy shifts and Rydberg structures

2012

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The behavior of strong-field ionization rates of neutral atoms in the vicinity of multiphoton ionization thresholds is analyzed using formal collision theory. Our approach, which accounts nonperturbatively for effects of an intense laser field, shows that the ionization rates have a nearly constant behavior below and above each multiphoton threshold and that between such thresholds there are an apparently finite number of rapid oscillations due to resonances with laser-field-modified Rydberg states. This pattern is typical for any atomic target, as we illustrate specifically for hydrogen and neon atoms. The flat behavior of the ionization yield near multiphoton thresholds gives the appearance of an energy shift of the ionization thresholds, which have been postulated in a number of recent studies concerning diverse aspects of above-threshold ionization and high-harmonic generation of atoms. The flat behaviors of the rates near threshold exhibit only a rather weak dependence on the laser-field intensity. Other aspects of the near-threshold behavior of ionization rates and their dependence on the laser-field parameters are also discussed.

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“…The correlation diagrams of Mulliken and Walsh (1)(2)(3) are valuable tools for developing this understanding, which should ultimately provide insight into a much broader class of nonadiabatic processes in small polyatomic molecules. Vibrational autoionization is perhaps best understood in the context of multichannel quantum defect theory (MQDT) (13)(14)(15). Thus, the remainder of this review begins with a discussion of some basic concepts of MQDT.…”

Section: Introductionmentioning

confidence: 99%

Vibrational autoionization in polyatomic molecules

Jungen

Pratt

1997

The Journal of Chemical Physics

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■ Abstract The vibrationally autoionizing Rydberg states of small polyatomic molecules provide a fascinating laboratory in which to study fundamental nonadiabatic processes. In this review, recent results on the vibrational mode dependence of vibrational autoionization are discussed. In general, autoionization rates depend strongly on the character of the normal mode driving the process and on the electronic character of the Rydberg electron. Although quantitative calculations based on multichannel quantum defect theory are available for some polyatomic molecules, including H 3 , only qualitative information exists for most molecules. This review shows how qualitative information, such as Walsh diagrams along different normal coordinates of the molecule, can provide insight into the vibrational autoionization rates.

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Molecular Applications of Quantum Defect Theory

Cited by 468 publications

References 137 publications

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

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

Threshold effects in strong-field ionization: Energy shifts and Rydberg structures

Vibrational autoionization in polyatomic molecules

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