Kr<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mo>(</mml:mo><mml:mi>n</mml:mi><mml:mo>=</mml:mo><mml:mn>5</mml:mn><mml:mo>–</mml:mo><mml:mn>10</mml:mn><mml:mo>,</mml:mo><mml:mtext mathvariant="italic">s,d,g</mml:mtext><mml:mo>)</mml:mo></mml:mrow></mml:math>electronic wave packets: Electron time-of-flight resolution and the ac-Stark shift during wave-packet preparation

Gilb, Stefan; Nestorov, Vilen K.; Leone, Stephen R.; Keske, John C.; Nugent-Glandorf, Lora; Grant, Edward R.

doi:10.1103/physreva.71.042709

Cited by 6 publications

(8 citation statements)

References 24 publications

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“…The time-independence of the anisotropy parameters has previously been observed in work exploring the PADs of twocolor two-photon excitation and ionization of helium 26 as well as in above threshold ionization measurements on argon 33 and helium. [45][46][47] If the superposition is probed to the same final state, the signal will contain a cross term that interferes the two excited states in the final continuum. [45][46][47] If the superposition is probed to the same final state, the signal will contain a cross term that interferes the two excited states in the final continuum.…”

Section: A Isolation Of J-state Anisotropy Parametersmentioning

confidence: 99%

Photoelectron angular distributions from autoionizing 4s14p66p1 states in atomic krypton probed with femtosecond time resolution

Doughty

Haber

Hackett

et al. 2011

The Journal of Chemical Physics

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Photoelectron angular distributions (PADs) are obtained for a pair of 4s(1)4p(6)6p(1) (a singlet and a triplet) autoionizing states in atomic krypton. A high-order harmonic pulse is used to excite the pair of states and a time-delayed 801 nm ionization pulse probes the PADs to the final 4s(1)4p(6) continuum with femtosecond time resolution. The ejected electrons are detected with velocity map imaging to retrieve the time-resolved photoelectron spectrum and PADs. The PAD for the triplet state is inherently separable by virtue of its longer autoionization lifetime. Measuring the total signal over time allows for the PADs to be extracted for both the singlet state and the triplet state. Anisotropy parameters for the triplet state are measured to be β(2)=0.55 ± 0.17 and β(4)=-0.01 ± 0.10, while the singlet state yields β(2)=2.19 ± 0.18 and β(4)=1.84 ± 0.14. For the singlet state, the ratio of radial transition dipole matrix elements, X, of outgoing S to D partial waves and total phase shift difference between these waves, Δ, are determined to be X=0.56 ± 0.08 and Δ=2.19 ± 0.11 rad. The continuum quantum defect difference between the S and D electron partial waves is determined to be -0.15 ± 0.03 for the singlet state. Based on previous analyses, the triplet state is expected to have anisotropy parameters independent of electron kinetic energy and equal to β(2)=5∕7 and β(4)=-12∕7. Deviations from the predicted values are thought to be a result of state mixing by spin-orbit and configuration interactions in the intermediate and final states; theoretical calculations are required to quantify these effects.

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Section: A Isolation Of J-state Anisotropy Parametersmentioning

confidence: 99%

Photoelectron angular distributions from autoionizing 4s14p66p1 states in atomic krypton probed with femtosecond time resolution

Doughty

Haber

Hackett

et al. 2011

The Journal of Chemical Physics

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“…Coherent excitation of atomic transitions by ultrashort laser pulses is a general way to excite wave packets and coherent transients, which have been the subject of several investigations. [1][2][3][4][5][6][7][8][9][10][11][12][13] Often, wave packet dynamics is studied by using pumpprobe techniques. In a typical pump-probe experiment, the pump laser initiates the dynamics by exciting a superposition of states.…”

Section: Introductionmentioning

confidence: 99%

“…However, these can be accompanied by ac Stark effects so that the analysis of the results can be difficult. 10,11 An extension of the investigation of these fundamental excitation processes from the near infrared to the extreme ultraviolet (XUV) regime has become feasible with the development of ultrashort XUV-radiation sources. High-order harmonic generation (HHG) of intense infrared laser radiation is a well-established approach leading to coherent XUV-as well as soft X-ray-sources.…”

Section: Introductionmentioning

confidence: 99%

Control of coherent excitation of neon in the extreme ultraviolet regime

et al. 2011

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Coherent excitation of a superposition of Rydberg states in neon by the 13th harmonic of an intense 804 nm pulse and the formation of a wave packet is reported. Pump-probe experiments are performed, where the 3d-manifold of the 2p6-->2p5 (2P3/2) 3d [1/2]1- and 2p6-->2p5 (2P3/2) 3d [3/2]1-transitions are excited by an extreme ultraviolet (XUV) radiation pulse, which is centered at 20.05 eV photon energy. The temporal evolution of the excited state population is probed by ionization with a time-delayed 804 nm pulse. Control of coherent transient excitation and wave packet dynamics in the XUV-regime is demonstrated, where the spectral phase of the 13th harmonic is used as a control parameter. Modulation of the phase is achieved by propagation of the XUV-pulse through neon of variable gas density. The experimental results indicate that phase-shaped high-order harmonics can be used to control fundamental coherent excitation processes in the XUV-regime.

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“…An important result is that the coherent superpositions are clearly formed during the Stark shifting process and are also preserved in the atoms when the laser field diminishes. 7 Even though an enormous number of states are excited simultaneously, high resolution detection and assignment of the quantum beats is possible. This is accomplished by resolving narrow slices of the outgoing electron kinetic energies, essentially a post-filtering of the detected states.…”

Section: 5-bridgingmentioning

confidence: 99%

“…states are made, 7 and measurements of their quantum defects are obtained. As expected, the quantum defects of the g states are small, since the electrons from g states do not penetrate significantly to the atomic core of the atoms.…”

Section: 5-bridgingmentioning

confidence: 99%

Ultrafast Soft X-Ray Probing of Core Level Molecular Dynamics

Leone¹

2006

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Public reporting; burden for tI~s collection of information is estimated to &verg o rperesponse, incldingdou h time for revievAning~structions, seareN nge istn data sources, athering and maintaining fth data needed, and completing an revawin thiscolaection of information.= Sen co rent garding Nos bken estimate or any o" aspeclt of hi cot ci no information.,r rigcu .u~atoi frrdun this burden to Department of Defense, Wasilington Headquarters Services, tDreclorate for tinformation operatiors anid AFRL-SR-AR-TR-07-O061Approved for Public Release; distribution is unlimited. SUPPLEMENTARY NOTES ABSTRACTThis research program explored time-resolved dynamics of molecular systems by femtosecond photoelectron spectroscopy using high order harmonics. Ultrafast soft x-ray laser pump/probe studies revealed changes in binding relations and atomic core level shifts in the molecules during chemical rearrangements by detecting the changes in photoelectron energies as a function of internuclear separation in dissociative states in real time.Harmonic pulses with photon energies up to 100 eV and femtosecond time resolution were produced with excellent efficiency and pulse-to-pulse stability.Valence and core photoelectron spectra were obtained on neutral atoms and molecules.Phase manipulation of high order harmonics was achieved.Photoelectron spectra and photoionization mass spectra of gas phase ionic liquids were obtained. Two color excitation spectra of bromine molecules were investigated, as well as Rydberg wave packet photoelectron angular distributions.Pump/probe experiments on the photodissociation of metal carbonyls, halogens, and aluminum halides were also under investigation. Executive Summary This research program explores the time-resolved reaction and fragmentation dynamics of diatomic and polyatomic molecules using femtosecond valence and core level photoelectron spectroscopy."' The chemical shifts in the electron energies provide direct information about the changes in electron orbital configurations as a function of internuclear separation in dissociative states of these molecules. Ultrafast soft x-ray laser pump/probe experiments take advantage of the femtosecond time resolution capability of a novel high order harmonic x-ray source by detecting time resolved valence electrons and atomic core level shifts in excited species as well as changes in the photo-ion mass distribution during chemical rearrangements. The experiments probe time-resolved valence (PES) and core level (XPS) spectroscopies on excited states and during photofragmentation of simple diatomics, metal halogen, and carbonyl species, as well as intramolecular processes in polyatomic molecules. The apparatus produces high order harmonics of a Ti:sapphire laser in the x-ray region of the spectrum with ultrafast pulse durations and is used to measure valence orbitals and atomic core levels during reactions and dissociation. The instrument consists of a 2.5 mJ pulse energy, 1000 Hz repetition rate Ti:sapphire laser system, a 1000 Hz pulsed jet of rare gas ...

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Kr(n=5–10,s,d,g)electronic wave packets: Electron time-of-flight resolution and the ac-Stark shift during wave-packet preparation

Cited by 6 publications

References 24 publications

Photoelectron angular distributions from autoionizing 4s14p66p1 states in atomic krypton probed with femtosecond time resolution

Photoelectron angular distributions from autoionizing 4s14p66p1 states in atomic krypton probed with femtosecond time resolution

Control of coherent excitation of neon in the extreme ultraviolet regime

Ultrafast Soft X-Ray Probing of Core Level Molecular Dynamics

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