Rydberg sequences

S. Svanberg Perturbations in Rydberg sequences probed by lifetime, Zeeman-effect and hyperfine structure measurements, in [Ref.9.23, p. 301]... 

Examples of atomic excited-state decay curves recorded with the transient digitizer technique for a sequence of states in sulphur are shown in Fig. 9.20. The lifetimes increase with a r oc trend as expected for a Rydberg sequence... 

Prilusky,J., Felder, C. E., Zeev-Ben-Mordehai, T., Rydberg, E. H., Man, O., Beckmann, J. S., Silman, I., and Sussman, J. L. (2005). Foldlndex A simple tool to predict whether a given protein sequence is intrinsically unfolded. Bioinformatics 21, 3435-3438. 

Prof. Schlag ( ZEKE Spectroscopy, this volume) has introduced a new sequential technique of ZEKE spectroscopy In the first step, a negative ion M is photoionized, yielding the neutral core M of the excited Rydberg state of the anion M. In the second step, M is further photoionized, yielding the cationic core M+ of the excited Rydberg state of the neutral molecule M. The overall sequence is thus... 

The spectrum (10.1.1) defines a doubly infinite sequence of states. They can be organized into series labelled by the first quantum number N. The states within a series are labelled by N. The first 12 series are shown in Fig. 10.1. For energies larger than Ejf, electron number 2 ionizes. Thus, every Rydberg series in Fig. 10.1 possesses an ionization continuum, which is also sketched. 

Fig. 10.11. Qualitative sketch (because of graphical reasons not to scale) of the repetitive sequence of three different dynamical regimes in the helium atom Ericson, Wigner and Rydberg. The Ericson and the Wigner regimes are manifestations of chaos in the helium atom.

Rydberg atoms and microwave fields constitute an ideal system for the study of atom-strong field effects, and they have been used to explore the entire range of one electron phenomena [5]. Here we focus on an illustrative example, which has a clear parallel in laser experiments, a series of experiments which show that apparently non-resonant microwave ionization of nonhydronic atoms proceeds via a sequence of resonant microwave multiphoton transitions and that this process can be understood quantitatively using a Floquet, or dressed state approach. 

The total duration of the control sequence shown in Fig. 4 is r 125 ns which is approximately 103 times shorter than the lifetime r/j/e = 0.115 ms of the Rydberg state 60/ as can be calculated from the spectroscopic data [Gallagher 1994], The different pulse timings range between 2.9 ns and 7.4 ns, which are feasible. They are reproduced in Tab. 1. 

The Natural Bond Orbital analysis of Weinhold [Foster and Weinhold, 1980 Reed, Weinstock etal., 1985 Reed, Curtiss etal., 1988] generates, departing from canonical MOs, a set of localized one center (core, lone pairs) and two center (jt and a bonds) strongly occupied orbitals, and a set of one center (Rydberg) and two center (a, Jt ) weakly occupied orbitals the NBOs. The Natural Bond Orbitals (NBOs) are obtained by a sequence of transformations from the input basis to give, first, the Natural Atomic Orbitals (NAOs), then the Natural Hybrid Orbitals (NHOs), and finally the Natural Bond Orbitals (NBOs). For NAOs, atomic charges can be calculated as a summation of contributions given by orbitals localized on each atom moreover, from NBOs, bond order can be also calculated. 

The first and/or second dye lasers were tuned to the specific wavelength(s) to populate the desired level(s). The final laser in the excitation sequence (either the second or third laser) was then continuously scanned to obtain the Rydberg or autoionization spectrum. The spectrum and wavelength calibrations were recorded simultaneously on a two pen recorder. Wavelength calibration was obtained by directing a portion of the scan laser radiation to a monochromator that was preset at known U or Th emission lines from an electrodless lamp. 

The Rydberg series of another member of the sequence, C2H5I, have also been studied [100]. They are more diffuse due the opening of new ionisation and dissociation channels and, as a result, cannot be followed to such high members. 

There exists, in addition, another possibility. It will not have escaped the reader that the two electrons, in the description just given, are not treated completely symmetrically. Were one to do so, it would be necessary to increase both nj and 2, so as to form a sequence of levels with n = 2 spaced differently from the normal Rydberg series, converging on the double-ionisation potential. At the limit of this series, both electrons would escape in a completely symmetric way, and so this possibility is often referred to as the double-escape problem . 

For large fields, the separation between Coulomb states becomes much smaller than the separation between quasi-Landau resonances, and one observes sequences of overlapping Rydberg channels distinguished by the... 

The prototypical indirect double photoionization process is the classical Auger effect, where the single-hole state created by ejection of an inner-shell electron exists for a significant time before ejection of a second electron. Alternatively, an intermediate singly charged state may exist as a multiply excited valence state or a Rydberg state, but whatever its nature, a lifetime of at least a few femtoseconds will normally allow the whole process to be considered as a sequence of two distinct steps. A sharp peak in the photoelectron spectrum and also, therefore, in... 

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