Effects of Direct Double Auger Decay on the Population Dynamics of Neon Irradiated by Ultraintense x‐ray Pulses

Cheng, Guangquan; Zeng, Jiaolong; Yuan, Jianmin

doi:10.1002/ctpp.201400061

Cited by 9 publications

(25 citation statements)

References 29 publications

(46 reference statements)

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“…Our choice of parameters produces a peak intensity of 2.2 × 10 17 W cm 2 which is consistent with 4.5 × 10 17 W cm 2 at a FWHM pulse duration of 140 fs used in Ref. 35 to produce similar theoretical ion yields as the ones shown in the lower panel with the modified rate equations. To achieve about the intensity of Ref.…”

Section: Ion Yields Of Neon Atomssupporting

confidence: 83%

“…Subsequent theoretical research [17,34,35] revealed that there are substantial further many-electron effects in neon in this case. Specifically, shake off following K-shell ionization [17] and double Auger decay of a K-shell vacancy [35] were included in extended rate-equation models for neon. This mitigated substantially the discrepancy found between the ion yields from the experiment and the plain rate equations.…”

Section: Introductionmentioning

confidence: 88%

“…To gain insights into the time-dependent quantum dynamics of the absorption of x rays and the resulting decay processes, we employ the rate-equation approximation [13,15,16,32,39] that has been used successfully in a number of studies to describe experiments, e.g., Refs. 9,12,13,15,17,31,[33][34][35][36]. Exemplary rate equations for a nitrogen atom restricted to K-shell electrons are given in Ref.…”

Section: X-ray Interaction With Neon Atomsmentioning

confidence: 99%

“…To achieve about the intensity of Ref. 35 we reduced the FWHM spot size of the x-ray beam. Without reducing the spot size, we would need a factor of 0.635 instead of 0.25 to determine the actual pulse energy from the nominal one; we consider this to be unrealistically high.…”

Section: Ion Yields Of Neon Atomsmentioning

confidence: 99%

“…The novel FEL facilities which produce x rays with unprecedented characteristics inspire one to investigate processes, known from the strong-field interaction of optical lasers with atoms, but with x rays that go be-Neon has been studied extensively in LCLS radiation both experimentally [12,17,31] and theoretically [32][33][34][35][36][37]. The quantum dynamics of neon atoms in intense and ultrashort x-ray radiation was initially described theoretically with a plain rate-equation model [12,32,33] that considered only one-photon cross sections and radiative and Auger decay widths.…”

Section: Introductionmentioning

confidence: 99%

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Neon in ultrashort and intense x-rays from free electron lasers

Buth

Beerwerth

Obaid

et al. 2018

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

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We theoretically examine neon atoms in ultrashort and intense x rays from free electron lasers and compare our results with data from experiments conducted at the Linac Coherent Light Source (LCLS). For this purpose, we treat in detail the electronic structure in all possible nonrelativistic cationic configurations using a relativistic multiconfiguration approach. The interaction with the x rays is described in rate-equation approximation. To understand the mechanisms of the interaction, a path analysis is devised which allows us to investigate what sequences of photoionization and decay processes lead to a specific configuration and with what probability. Thereby, we uncover a connection to the mathematics of graph theory and formal languages. In detail, we study the ion yields and find that plain rate equations do not provide a satisfactory description. We need to extend the rate equations for neon to incorporate double Auger decay of a K-shell vacancy and photoionization shake off for neutral neon. Shake off is included for valence and core ionization; the former has hitherto been overlooked but has important consequences for the ion yields from an x-ray energy below the core ionization threshold. Furthermore, we predict the photon yields from xuv and x-ray fluorescence; these allow one insights into the configurations populated by the interaction with the x rays. Finally, we discover that inaccuracies in those Auger decay widths employed in previous studies have only a minor influence on ion and photon yields.Keywords: ultrashort and intense x rays, neon atom, multiconfiguration Dirac-Hartre-Fock, rate equations, free-electron laser, ion yield, photon yield I. INTRODUCTIONAtoms are the basic constituents of aggregates of matter realized in molecules, clusters, and solids. In this way, the study of the interaction of intense and ultrafast x rays with atoms is of fundamental importance for all research involving matter in such light. Intense x rays offer manifold novel perspectives for science such as diffraction experiments with single molecules [1] and x-ray quantum optics [2].Experimentally, research with intense and ultrafast x rays has only recently become a reality by the novel x-ray free electron lasers (FELs) of which there are presently four producing soft to hard x rays: the Linac Coherent Light Source (LCLS) [3,4] in Menlo Park, California, USA, the SPring-8 Angstrom Compact free electron LAser (SACLA) [5] in Sayo-cho, Sayo-gun, Hyogo, Japan, the SwissFEL [6] in Villigen, Switzerland, and the European X-Ray Free-Electron Laser (XFEL) [7] in Hamburg, Germany.The novel FEL facilities which produce x rays with unprecedented characteristics inspire one to investigate processes, known from the strong-field interaction of optical lasers with atoms, but with x rays that go be- * World Wide Web: www.christianbuth.name, electronic mail; christian.buth@web.de yond the well-established one-x-ray-photon science only possible at synchrotron light sources [8]. With x rays the sequential absorption of multiple pho...

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Section: Ion Yields Of Neon Atomssupporting

confidence: 83%