Interferences in photoexcited double-excitation series of He

Domke, M.; Schulz, K.; Remmers, G.; Gutiérrez, Alejandro; Kaindl, G.; Wintgen, Dieter

doi:10.1103/physreva.51.r4309

Cited by 79 publications

(114 citation statements)

References 7 publications

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“…The mutual interaction of the Rydberg series in the energy regime shown in Fig. 5 can still be treated within quantum defect theory (Seaton, 1983); see, for example, Domke et al (1991Domke et al ( , 1995. This is only possible for moderate N, where individual perturbers can still be identified.…”

Section: Basic Spectral Propertiesmentioning

confidence: 99%

The theory of two-electron atoms: between ground state and complete fragmentation

2000

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Since the first attempts to calculate the helium ground state in the early days of Bohr-Sommerfeld quantization, two-electron atoms have posed a series of unexpected challenges to theoretical physics. Despite the seemingly simple problem of three charged particles with known interactions, it took more than half a century after quantum mechanics was established to describe the spectra of two-electron atoms satisfactorily. The evolution of the understanding of correlated two-electron dynamics and its importance for doubly excited resonance states is presented here, with an emphasis on the concepts introduced. The authors begin by reviewing the historical development and summarizing the progress in measuring the spectra of two-electron atoms and in calculating them by solving the corresponding Schrö dinger equation numerically. They devote the second part of the review to approximate quantum methods, in particular adiabatic and group-theoretical approaches. These methods explain and predict the striking regularities of two-electron resonance spectra, including propensity rules for decay and dipole transitions of resonant states. This progress was made possible through the identification of approximate dynamical symmetries leading to corresponding collective quantum numbers for correlated electron-pair dynamics. The quantum numbers are very different from the independent particle classification, suitable for low-lying states in atomic systems. The third section of the review describes modern semiclassical concepts and their application to two-electron atoms. Simple interpretations of the approximate quantum numbers and propensity rules can be given in terms of a few key periodic orbits of the classical three-body problem. This includes the puzzling existence of Rydberg series for electron-pair motion. Qualitative and quantitative semiclassical estimates for doubly excited states are obtained for both regular and chaotic classical two-electron dynamics using modern semiclassical techniques. These techniques set the stage for a theoretical investigation of the regime of extreme excitation towards the three-body breakup threshold. Together with periodic orbit spectroscopy, they supply new tools for the analysis of complex experimental spectra.

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Section: Basic Spectral Propertiesmentioning

confidence: 99%

The theory of two-electron atoms: between ground state and complete fragmentation

2000

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“…Since the first experiment by Madden and Codling (1963) doubly excited states of helium have attracted the interest of theoreticians and experimentalists. Recent experiments study with high resolution the photoabsorption of helium to doubly excited states (Domke et al 1991(Domke et al , 1992(Domke et al , 1995. Numerous theoretical investigations have improved our understanding of the electron-electron correlation which prevents an analytical solution for the helium atom.…”

Section: Introductionmentioning

confidence: 99%

Highly doubly excited S states of the helium atom

Bürgers

Wintgen

Rest

1995

J. Phys. B: At. Mol. Opt. Phys.

171

147

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We calculate and analyse S-wave resonances of helium up to an energy of-0.02 au applying the complex rotation technique. Rydkrg series converging to the hydrogenic thresholds of the Het ion are analysed by quantum defect theory. For moderately excited inner electrons the series converging to different thresholds begin to overlap resulting in perturbed Rydberg series. We find that approximate quantum numbers as well as propensity rules governing the decay of the resonances and the perturbation scheme of the Rydberg aeries prevail. With increasing excitation of the inner electran however, only series whose stiltes tend lo extreme interelectronic angles (cos0) = + I remain regular.

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“…Thereafter, many of experimental studies [10][11][12][13][14][15][16] were carried out on the double excitations of helium until the first observation of the missing Rydberg series by Domke et al [17]. With the development of the synchrotron radiation technique, more sophisticated photoionization experiments were performed to acquire the higher Rydberg series above the N = 2 threshold of He + [18][19][20], decay paths of two-electron excitations [21][22][23][24][25], photoelectron angular distributions [26], threshold energies [27], interseries interferences [28], dipolequadrupole interference [29], and so on.…”

Section: Introductionmentioning

confidence: 99%

Theoretical investigations on the dynamical correlation in double excitations of helium by theR-matrix method

et al. 2004

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The momentum transfer dependence of double excitations of helium were studied theoretically in order to compare with our previous experimental work [Phys. Rev. Lett. 91, 193203 (2003)]. The calculation was carried out by a series of modified R-matrix codes. We elucidate the dynamical correlations in terms of the internal correlation quantum numbers K, T, and A. The generalized oscillator strength densities and Fano profile parameters q, f a , f, and S of doubly excited states n ͑1,0͒ 2 + 1 S e , n ͑1,0͒ 2 + 1 D e , and n ͑0,1͒ 2 + 1 P o were reported as functions of the momentum transfer squared K 2 . The present theoretical work accompanied by our previous experiment leads to a deep understanding of the optically allowed and optically forbidden double excitations of helium.

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Interferences in photoexcited double-excitation series of He

Cited by 79 publications

References 7 publications

The theory of two-electron atoms: between ground state and complete fragmentation

The theory of two-electron atoms: between ground state and complete fragmentation

Highly doubly excited S states of the helium atom

Theoretical investigations on the dynamical correlation in double excitations of helium by theR-matrix method

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