Coulomb explosion of diatomic molecules in intense XUV fields mapped by partial covariance

Kornilov, Oleg; Eckstein, Martin; Rosenblatt, Marcus; Schulz, Claus-Peter; Motomura, K.; Rouzée, Arnaud; Klei, J.; Foucar, L.; Siano, M.; Lübcke, A.; Schapper, F.; Johnsson, Per; Holland, D.M.P.; Schlathölter, Thomas; Marchenko, T.; Düsterer, S.; Ueda, Kiyoshi; Vrakking, Marc J. J.; Frasinski, L. J.

doi:10.1088/0953-4075/46/16/164028

Cited by 35 publications

(32 citation statements)

References 32 publications

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“…One solution to this predicament is to perform covariance analysis, in which statistically significant relationships between various detected particles are looked for, not on an event-by event basis, but by using statistical analysis methods [30][31][32][33][34]. Covariance analysis has been shown to extract useful information even from datasets with high ionization rates per pulse.…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics of XFEL-Induced Photo-Dissociation, Revealed by Ion-Ion Coincidence Measurements

et al. 2017

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X-ray free electron lasers (XFELs) providing ultrashort intense pulses of X-rays have proven to be excellent tools to investigate the dynamics of radiation-induced dissociation and charge redistribution in molecules and nanoparticles. Coincidence techniques, in particular multi-ion time-of-flight (TOF) coincident experiments, can provide detailed information on the photoabsorption, charge generation, and Coulomb explosion events. Here we review several such recent experiments performed at the SPring-8 Angstrom Compact free electron LAser (SACLA) facility in Japan, with iodomethane, diiodomethane, and 5-iodouracil as targets. We demonstrate how to utilize the momentum-resolving capabilities of the ion TOF spectrometers to resolve and filter the coincidence data and extract various information essential in understanding the time evolution of the processes induced by the XFEL pulses.

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Section: Introductionmentioning

confidence: 99%

Molecular Dynamics of XFEL-Induced Photo-Dissociation, Revealed by Ion-Ion Coincidence Measurements

et al. 2017

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“…In other practical applications of covariance analysis, other unstable parameters might be of similar significance. If the value of I can be measured from shot to shot and the event rate relates linearly to it, X ∝ I , the approach of partial covariance mapping [17][18][19]22] can be employed to correct for possible contributions associated with the varying experimental parameter considered,…”

Section: Partial Covariance Mappingmentioning

confidence: 99%

“…On that basis we can make use of simple linear regression as follows to obtain linear approximations for the signals of interest as a function of the unstable parameter I [27]: Simulation results based on this equation and carried out in the same way as above using Eq. (19) are shown in the right panels of Fig. 5 where they are compared with results based on the total covariance mapping approach (left panels) discussed before.…”

Section: Partial Covariance Mapping In Three Dimensionsmentioning

confidence: 99%

“…Several data-analysis methods enabling drastic reduction of accidental events have been reported in the literature [13][14][15]. An elegant technique is covariance mapping, which was introduced to the field of photoionization in 1989 by Frasinski and coworkers [16] and has been recently applied to analysis of atomic [17,18] and molecular [19] fragmentation induced by intense FEL pulses. Very recently, two theoretical papers have been published [20,21] that elaborate on the mathematical description of the covariance analysis published in much earlier papers [16,22,23].…”

Section: Introductionmentioning

confidence: 99%

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Theory and simulations of covariance mapping in multiple dimensions for data analysis in high-event-rate experiments

et al. 2014

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Multidimensional covariance analysis and its validity for correlation of processes leading to multiple products are investigated from a theoretical point of view. The need to correct for false correlations induced by experimental parameters which fluctuate from shot to shot, such as the intensity of self-amplified spontaneous emission x-ray free-electron laser pulses, is emphasized. Threefold covariance analysis based on simple extension of the two-variable formulation is shown to be valid for variables exhibiting Poisson statistics. In this case, false correlations arising from fluctuations in an unstable experimental parameter that scale linearly with signals can be eliminated by threefold partial covariance analysis, as defined here. Fourfold covariance based on the same simple extension is found to be invalid in general. Where fluctuations in an unstable parameter induce nonlinear signal variations, a technique of contingent covariance analysis is proposed here to suppress false correlations. In this paper we also show a method to eliminate false correlations associated with fluctuations of several unstable experimental parameters.

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“…An "island" in the covariance map corresponding to these kinetic energies should be present. It has previously been demonstrated that electronelectron covariance is feasible at FELs (at both FLASH and LCLS) 35,36 . Other processes that will give two correlated electrons in the same energy range are Fig.…”

Section: Experimental Implementation: Feasibility With Current X-ray mentioning

confidence: 99%

Analysis of a measurement scheme for ultrafast hole dynamics by few femtosecond resolution X-ray pump–probe Auger spectroscopy

et al. 2014

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Ultrafast hole dynamics created in molecular systems as a result of sudden ionisation are the focus of much attention in the field of attosecond science. Using the molecule glycine we show through ab-initio simulations that the dynamics of a hole, arising from ionisation in the inner valence region, evolve with a timescale appropriate to be measured using X-ray pulses from the current generation of SASE free electron lasers. The examined pump-probe scheme uses X-rays with photon energy below the K edge of carbon (275-280 eV) that will ionise from the inner valence region. A second probe X-ray at the same energy can excite an electron from the core to fill the vacancy in the inner-valence region. The dynamics of the inner valence hole can be tracked by measuring the Auger electrons produced by the subsequent refilling of the core hole as a function of pump-probe delay. We consider the feasibility of the experiment and include a numerical simulation to support this analysis. We discuss the potential for all X-ray pump-X-ray probe Auger spectroscopy measurements for tracking hole migration.

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Coulomb explosion of diatomic molecules in intense XUV fields mapped by partial covariance

Cited by 35 publications

References 32 publications

Molecular Dynamics of XFEL-Induced Photo-Dissociation, Revealed by Ion-Ion Coincidence Measurements

Molecular Dynamics of XFEL-Induced Photo-Dissociation, Revealed by Ion-Ion Coincidence Measurements

Theory and simulations of covariance mapping in multiple dimensions for data analysis in high-event-rate experiments

Analysis of a measurement scheme for ultrafast hole dynamics by few femtosecond resolution X-ray pump–probe Auger spectroscopy

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