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Fung R, Hanna AM, Vendrell O, Ramakrishna S, Seideman T, Santra R, Ourmazd A, Ourmazd A. Dynamics from noisy data with extreme timing uncertainty. Nature 2016; 532:471-5. [PMID: 27121840 DOI: 10.1038/nature17627] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 02/18/2016] [Indexed: 11/09/2022]
Abstract
Imperfect knowledge of the times at which 'snapshots' of a system are recorded degrades our ability to recover dynamical information, and can scramble the sequence of events. In X-ray free-electron lasers, for example, the uncertainty--the so-called timing jitter--between the arrival of an optical trigger ('pump') pulse and a probing X-ray pulse can exceed the length of the X-ray pulse by up to two orders of magnitude, marring the otherwise precise time-resolution capabilities of this class of instruments. The widespread notion that little dynamical information is available on timescales shorter than the timing uncertainty has led to various hardware schemes to reduce timing uncertainty. These schemes are expensive, tend to be specific to one experimental approach and cannot be used when the record was created under ill-defined or uncontrolled conditions such as during geological events. Here we present a data-analytical approach, based on singular-value decomposition and nonlinear Laplacian spectral analysis, that can recover the history and dynamics of a system from a dense collection of noisy snapshots spanning a sufficiently large multiple of the timing uncertainty. The power of the algorithm is demonstrated by extracting the underlying dynamics on the few-femtosecond timescale from noisy experimental X-ray free-electron laser data recorded with 300-femtosecond timing uncertainty. Using a noisy dataset from a pump-probe experiment on the Coulomb explosion of nitrogen molecules, our analysis reveals vibrational wave-packets consisting of components with periods as short as 15 femtoseconds, as well as more rapid changes, which have yet to be fully explored. Our approach can potentially be applied whenever dynamical or historical information is tainted by timing uncertainty.
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Affiliation(s)
- R Fung
- Department of Physics, University of Wisconsin Milwaukee, 3135 North Maryland Avenue, Milwaukee, Wisconsin 53211, USA
| | - A M Hanna
- Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Luruper Chausee 149, 22761 Hamburg, Germany.,Department of Chemistry, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany
| | - O Vendrell
- Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Luruper Chausee 149, 22761 Hamburg, Germany
| | - S Ramakrishna
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA
| | - T Seideman
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, USA
| | - R Santra
- Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Luruper Chausee 149, 22761 Hamburg, Germany.,Department of Chemistry, University of Hamburg, Grindelallee 117, 20146 Hamburg, Germany.,Department of Physics, University of Hamburg, Jungiusstrasse 9, 20355 Hamburg, Germany
| | - A Ourmazd
- Department of Physics, University of Wisconsin Milwaukee, 3135 North Maryland Avenue, Milwaukee, Wisconsin 53211, USA
| | - A Ourmazd
- Department of Physics, University of Wisconsin Milwaukee, 3135 North Maryland Avenue, Milwaukee, Wisconsin 53211, USA
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Wu J, Gong X, Kunitski M, Amankona-Diawuo FK, Schmidt LPH, Jahnke T, Czasch A, Seideman T, Dörner R. Strong field multiple ionization as a route to electron dynamics in a van der Waals cluster. Phys Rev Lett 2013; 111:083003. [PMID: 24010435 DOI: 10.1103/physrevlett.111.083003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2013] [Indexed: 06/02/2023]
Abstract
We study the order in which a strong laser field removes multiple electrons from a van der Waals (vdW) cluster. The N2Ar, with an equilibrium T-shaped geometry, contains both a covalent and a vdW bond and serves as a simple yet rich example. Interestingly, the fragmenting double and triple ionizations of N2Ar with vdW bond breaking are favored when the vdW bond is aligned along the laser field polarization vector. However, the orientation of the covalent bond with respect to the laser field rules the triple ionization when both the covalent and vdW bonds are simultaneously broken. Electron-localization-assisted enhanced ionization and molecular orbital profile-dominated, orientation-dependent ionization are discussed to reveal the order of electrons release from different sites of N2Ar.
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Affiliation(s)
- J Wu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, China
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3
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Jiang N, Foley ET, Klingsporn JM, Sonntag MD, Valley NA, Dieringer JA, Seideman T, Schatz GC, Hersam MC, Van Duyne RP. Observation of multiple vibrational modes in ultrahigh vacuum tip-enhanced Raman spectroscopy combined with molecular-resolution scanning tunneling microscopy. Nano Lett 2012; 12:5061-7. [PMID: 22200250 DOI: 10.1021/nl2039925] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Multiple vibrational modes have been observed for copper phthalocyanine (CuPc) adlayers on Ag(111) using ultrahigh vacuum (UHV) tip-enhanced Raman spectroscopy (TERS). Several important new experimental features are introduced in this work that significantly advance the state-of-the-art in UHV-TERS. These include (1) concurrent sub-nm molecular resolution STM imaging using Ag tips with laser illumination of the tip-sample junction, (2) laser focusing and Raman collection optics that are external to the UHV-STM that has two cryoshrouds for future low temperature experiments, and (3) all sample preparation steps are carried out in UHV to minimize contamination and maximize spatial resolution. Using this apparatus we have been able to demonstrate a TERS enhancement factor of 7.1 × 10(5). Further, density-functional theory calculations have been carried out that allow quantitative identification of eight different vibrational modes in the TER spectra. The combination of molecular-resolution UHV-STM imaging with the detailed chemical information content of UHV-TERS allows the interactions between large polyatomic molecular adsorbates and specific binding sites on solid surfaces to be probed with unprecedented spatial and spectroscopic resolution.
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Affiliation(s)
- N Jiang
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, USA
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4
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Lock RM, Ramakrishna S, Zhou X, Kapteyn HC, Murnane MM, Seideman T. Extracting continuum electron dynamics from high harmonic emission from molecules. Phys Rev Lett 2012; 108:133901. [PMID: 22540700 DOI: 10.1103/physrevlett.108.133901] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Indexed: 05/31/2023]
Abstract
We show that high harmonic generation is the most sensitive probe of rotational wave packet revivals, revealing very high-order rotational revivals for the first time using any probe. By fitting high-quality experimental data to an exact theory of high harmonic generation from aligned molecules, we can extract the underlying electronic dipole elements for high harmonic emission and uncover that the electron gains angular momentum from the photon field.
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Affiliation(s)
- R M Lock
- Department of Physics and JILA, University of Colorado and NIST, Boulder, Colorado 80309, USA.
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5
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Floß J, Grohmann T, Leibscher M, Seideman T. Nuclear spin selective laser control of rotational and torsional dynamics. J Chem Phys 2012; 136:084309. [DOI: 10.1063/1.3687343] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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Abstract
We examine the coupling of electromagnetic waves incident normal to a thin silver film that forms an oscillatory grating embedded between two otherwise uniform, semi-infinite half spaces. Two grating structures are considered, in one of which the midpoint of the Ag film remains fixed whereas the thickness varies sinusoidally, while in the other the mid point oscillates sinusoidally whereas the film thickness remains fixed. On reducing the light wavelength from the long wavelength limit, we encounter signatures in the transmission, T, and reflection, R, coefficients associated with: (i) the short-range surface plasmon mode, (ii) the long-range surface plasmon mode, and (iii) electromagnetic diffraction tangent to the grating. The first two features can be regarded as generalized (plasmon) Wood's anomalies whereas the third is the first-order conventional (electromagnetic) Wood's anomaly. The energy density at the film surface is enhanced for wavelengths corresponding to these three anomalies, particularly for the long-range plasmon mode in thin films. When exciting the silver film with a pair of waves incident from opposite directions, we find that by adjusting the grating oscillation amplitude and fixing the relative phase of the incoming waves to be even or odd, T+R can be made to vanish for one or the other of the plasmon modes; this corresponds to perfect coupling (impedance matching in the language of electrical engineering) between the incoming light and these modes.
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Affiliation(s)
- M Sukharev
- Department of Applied Sciences and Mathematics, Arizona State University at the Polytechnic Campus, Mesa, Arizona 85212, USA.
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8
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Gay G, Alloschery O, Weiner J, Lezec HJ, O'Dwyer C, Sukharev M, Seideman T. Surface quality and surface waves on subwavelength-structured silver films. Phys Rev E Stat Nonlin Soft Matter Phys 2007; 75:016612. [PMID: 17358280 DOI: 10.1103/physreve.75.016612] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2006] [Indexed: 05/14/2023]
Abstract
We analyze the physical-chemical surface properties of single-slit, single-groove subwavelength-structured silver films with high-resolution transmission electron microscopy and calculate exact solutions to Maxwell's equations corresponding to recent far-field interferometry experiments using these structures. Contrary to a recent suggestion the surface analysis shows that the silver films are free of detectable contaminants. The finite-difference time-domain calculations, in excellent agreement with experiment, show a rapid fringe amplitude decrease in the near zone (slit-groove distance out to 3-4 wavelengths). Extrapolation to slit-groove distances beyond the near zone shows that the surface wave evolves to the expected bound surface plasmon polariton (SPP). Fourier analysis of these results indicates the presence of a distribution of transient, evanescent modes around the SPP that dephase and dissipate as the surface wave evolves from the near to the far zone.
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Affiliation(s)
- G Gay
- IRSAMC/LCAR, Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse, France
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9
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Yoder NL, Guisinger NP, Hersam MC, Jorn R, Kaun CC, Seideman T. Quantifying desorption of saturated hydrocarbons from silicon with quantum calculations and scanning tunneling microscopy. Phys Rev Lett 2006; 97:187601. [PMID: 17155577 DOI: 10.1103/physrevlett.97.187601] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2006] [Indexed: 05/12/2023]
Abstract
Electron stimulated desorption of cyclopentene from the Si(100)-(2 x 1) surface is studied experimentally with cryogenic UHV STM and theoretically with transport, electronic structure, and dynamical calculations. Unexpectedly for a saturated hydrocarbon on silicon, desorption is observed at bias magnitudes as low as 2.5 V, albeit the desorption yields are a factor of 500 to 1000 lower than previously reported for unsaturated molecules on silicon. The low threshold voltage for desorption is attributed to hybridization of the molecule with the silicon surface, which results in low-lying ionic resonances within 2-3 eV of the Fermi level. These resonances are long-lived, spatially localized, and displaced in equilibrium with respect to the neutral state. This study highlights the importance of nuclear dynamics in silicon-based molecular electronics and suggests new guidelines for the control of such dynamics.
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Affiliation(s)
- N L Yoder
- Department of Materials Science and Engineering, Northwestern University, 2220 Campus Drive, Evanston, Illinois 60208-3108, USA
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Abstract
We propose the application of the contact potential from metal-metal junctions or the built-in potential of semiconductor p-n junctions to induce or catalyze chemical reactions. Free of external sources, this intrinsic potential across microscale and nanoscale vacuum gaps establishes electric fields in excess of 10(7) Vm. The electrostatic potential energy of these fields can be converted into useful chemical energy. As an example, we focus on the production of superthermal gas ions to drive reactions. Analysis indicates that this intrinsically biased electrocapacitive catalysis can achieve locally directed ion energies up to a few electron volts and local gas temperature boosts in excess of 10(4) K. Practical considerations for implementation and experimental tests are considered.
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Affiliation(s)
- D P Sheehan
- Department of Physics, University of San Diego, California 92110, USA.
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11
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Alavi S, Rousseau R, Lopinski GP, Wolkow RA, Seideman T. Controlling organic reactions on silicon surfaces with a scanning tunneling microscope: theoretical and experimental studies of resonance-mediated desorption. Faraday Discuss 2001:213-29; discussion 257-75. [PMID: 11271993 DOI: 10.1039/b004093m] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The dynamics of tip-induced, resonance-mediated bond-breaking in complex organic adsorbates is studied theoretically and experimentally. Desorption of benzene from a Si(100) surface is found to be efficient and sensitive to voltage, the measured yield rising from below 10(-10) to ca. 10(-6) per electron within a ca. 0.8 V range at low (< 100 pA) current. A theoretical model, based upon first principles electronic structure calculations and quantum mechanical wavepacket simulations, traces these observations to multi-mode dynamics triggered by a transition into a cationic resonance. The model is generalized to provide understanding of, and suggest a means of control over, the behaviour of different classes of organic adsorbates under tunneling current.
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Affiliation(s)
- S Alavi
- Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, Ontario, K1A 0R6, Canada
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12
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Unny S, Du Y, Zhu L, Gordon RJ, Sugita A, Kawasaki M, Matsumi Y, Seideman T. Above-threshold dissociative ionization in the intermediate intensity regime. Phys Rev Lett 2001; 86:2245-2248. [PMID: 11289900 DOI: 10.1103/physrevlett.86.2245] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2000] [Indexed: 05/23/2023]
Abstract
The problem of dissociative ionization at intermediate intensities ( 10(10)-10(12) W cm(-2)) was studied using the example of I2 and the technique of velocity map imaging. Several new phenomena were observed, including a continuous distribution of recoil energies peaked at zero-kinetic energy, a set of constant dissociative ionic states, and strong anisotropy of the fragment velocity distribution that is diminished by intermediate resonances.
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Affiliation(s)
- S Unny
- Department of Chemistry (m/c 111), University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, USA
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13
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Moudrakovski IL, Breeze SR, Simard B, Ratcliffe CI, Ripmeester JA, Seideman T, Tse JS, Santyr G. Gas-phase nuclear magnetic relaxation in 129Xe revisited. J Chem Phys 2001. [DOI: 10.1063/1.1337804] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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14
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Alavi S, Rousseau R, Patitsas SN, Lopinski GP, Wolkow RA, Seideman T. Inducing desorption of organic molecules with a scanning tunneling microscope: theory and experiments. Phys Rev Lett 2000; 85:5372-5375. [PMID: 11135999 DOI: 10.1103/physrevlett.85.5372] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2000] [Indexed: 05/23/2023]
Abstract
A scanning-tunneling microscope has been used to induce efficient local desorption of benzene from Si(100) at low currents (<100 pA), sample biases (approximately -2.4 V) and temperatures (22 K). A theoretical model based upon first principles electronic structure calculations and quantum mechanical wave packet dynamics describes this process as occurring via transient ionization of a pi state of the adsorbed molecule. This model accounts for the unexpected efficiency and sharp threshold of the yield.
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Affiliation(s)
- S Alavi
- Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, Ontario, K1A 0R6
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15
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Blanchet V, Lochbrunner S, Schmitt M, Shaffer JP, Larsen JJ, Zgierski MZ, Seideman T, Stolow A. Towards disentangling coupled electronic-vibrational dynamics in ultrafast non-adiabatic processes. Faraday Discuss 2000:33-48; discussion 79-102. [PMID: 11040499 DOI: 10.1039/b001138j] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Femtosecond time-resolved photoelectron spectroscopy is emerging as a new technique for investigating polyatomic excited state dynamics. Due to the sensitivity of photoelectron spectroscopy to both electronic configurations and vibrational dynamics, it is well suited to the study of non-adiabatic processes such as internal conversion, which often occur on sub-picosecond time scales. We discuss the technical requirements for such experiments, including lasers systems, energy- and angle-resolved photoelectron spectrometers and new detectors for coincidence experiments. We present a few examples of these methods applied to problems in diatomic wavepacket dynamics and ultrafast non-adiabatic processes in polyatomic molecules.
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Affiliation(s)
- V Blanchet
- Steacie Institute for Molecular Sciences, National Research Council of Canada, Ottawa, Ontario, Canada
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Larsen JJ, Hald K, Bjerre N, Stapelfeldt H, Seideman T. Three dimensional alignment of molecules using elliptically polarized laser fields. Phys Rev Lett 2000; 85:2470-2473. [PMID: 10978084 DOI: 10.1103/physrevlett.85.2470] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2000] [Indexed: 05/23/2023]
Abstract
We demonstrate, theoretically and experimentally, that an intense, elliptically polarized, nonresonant laser field can simultaneously force all three axes of a molecule to align along given axes fixed in space, thus inhibiting the free rotation in all three Euler angles. Theoretically, the effect is illustrated through time dependent quantum mechanical calculations. Experimentally, 3, 4-dibromothiophene molecules are aligned with a nanosecond laser pulse. The alignment is probed by 2D ion imaging of the fragments from a 20 fs laser pulse induced Coulomb explosion.
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Affiliation(s)
- JJ Larsen
- Institute of Physics and Astronomy, University of Arhus, DK-8000 Arhus C, Denmark
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17
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Fiss JA, Khachatrian A, Truhins K, Zhu L, Gordon RJ, Seideman T. Direct observation of a breit-wigner phase of a wave function. Phys Rev Lett 2000; 85:2096-2099. [PMID: 10970471 DOI: 10.1103/physrevlett.85.2096] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2000] [Indexed: 05/23/2023]
Abstract
The Breit-Wigner phase of a wave function was obtained by measuring the interference between two independent ionization paths of a molecule. The state of interest was present in only one of the paths, thereby producing a phase shift in the observed signal. An analytical theory was used to determine the phase of the wave function from the observable.
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Affiliation(s)
- JA Fiss
- Department of Chemistry (m/c 111), University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, USA
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18
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Haran A, Kadyshevitch A, Cohen H, Naaman R, Evans D, Seideman T, Nitzan A. Electron transmission through band structure in organized organic thin films. Chem Phys Lett 1997. [DOI: 10.1016/s0009-2614(97)00230-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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19
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Ivanov M, Seideman T, Corkum P, Ilkov F, Dietrich P. Explosive ionization of molecules in intense laser fields. Phys Rev A 1996; 54:1541-1550. [PMID: 9913624 DOI: 10.1103/physreva.54.1541] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Seideman T, Shapiro M, Vager Z. Theory of the coherent decay of high-lying Rydberg states in beam-foil encounters. Phys Rev A Gen Phys 1987; 35:87-102. [PMID: 9897932 DOI: 10.1103/physreva.35.87] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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