The Political Philosophy of Niccolò Machiavelli

Lucchese, Filippo Del

doi:10.1515/9781474404297

Cited by 30 publications

(7 citation statements)

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“…Ionization matrix elements, which include the full scattering phase, were calculated using the ePolyScat suite of codes, distributed by R. R. Lucchese (for further details see refs. [26][27][28]). These calculations take input from standard electronic structure codes (Gamess, Gaussian etc.)…”

Section: Group Delay In the Molecular Frame A Numerical Detailsmentioning

confidence: 99%

“…Although the details are specific to valence ionization of N 2 and CO, the results may be considered as prototypical for molecular ionization. As detailed below (section 3), we make use of ePolyScat [26][27][28], a well-developed suite of codes from the scattering community, to solve the numerical integrals for arbitrary molecular potentials, thus our methodology is completely general and can be readily applied to polyatomic molecules. We finish by discussing some attosecond metrology concepts which could provide deeper experimental insight into ionization time delays in an angle and energy resolved manner.…”

Section: Introductionmentioning

confidence: 99%

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Time delay in molecular photoionization

Hockett

Frumker

Villeneuve

et al. 2016

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

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Time-delays in the photoionization of molecules are investigated. As compared to atomic ionization, the time-delays expected from molecular ionization present a much richer phenomenon, with a strong spatial dependence due to the anisotropic nature of the molecular scattering potential. We investigate this from a scattering theory perspective, and make use of molecular photoionization calculations to examine this effect in representative homonuclear and hetronuclear diatomic molecules, nitrogen and carbon monoxide. We present energy and angle-resolved maps of the Wigner delay time for single-photon valence ionization, and discuss the possibilities for experimental measurements.

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Section: Group Delay In the Molecular Frame A Numerical Detailsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Time delay in molecular photoionization

Hockett

Frumker

Villeneuve

et al. 2016

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

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“…In order to treat real systems within the framework defined herein, a numerical treatment for the photoionization matrix elements (specifically, the radial integrals) for a given ionizing system is required. In this work, the bound-free matrix elements are computed using the ePolyScat (ePS) suite [36][37][38], and the continuum-continuum matrix elements treated as hydrogenic (similar to the treatment of [3]). This specific choice of numerical treatment is general, since ePS is capable of accurate calculations for both atomic and molecular scattering systems, but is expected to be poor at low energies where the assumption of hydrogenic continuum-continuum transitions does not hold.…”

Section: Real Systemsmentioning

confidence: 99%

“…For a given ionizing system and ionizing orbital, ePs can be used to compute dipole matrix elements. ePS takes electronic structure input from standard quantum chemistry codes, solves the continuum wavefunctions variationally with a Lipmann-Schwinger approach, and computes dipole integrals based on these wavefunctions; for further details, see [36][37][38]. • Continuum-continuum matrix elements.…”

Section: Numerical Detailsmentioning

confidence: 99%

Angle-resolved RABBITT: theory and numerics

Hockett

2017

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

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I. ABSTRACTAngle-resolved (AR) RABBIT measurements offer a high information content measurement scheme, due to the presence of multiple, interfering, ionization channels combined with a phase-sensitive observable in the form of angle and time-resolved photoelectron interferograms. In order to explore the characteristics and potentials of AR-RABBIT, a perturbative 2-photon model is developed; based on this model, example AR-RABBIT results are computed for model and real systems, for a range of RABBIT schemes. These results indicate some of the phenomena to be expected in AR-RABBIT measurements, and suggest various applications of the technique in photoionization metrology. Article history• arXiv (this version) The RABBIT methodology -"reconstruction of attosecond harmonic beating by interference of two-photon transitions" [1] -essentially defines a scheme in which XUV pulses are combined with an IR field, and the two fields are applied to a target gas. The gas is ionized, and the photoelectrons detected. In the typical case, the IR field is at the same fundamental frequency ω as the field used to drive harmonic generation, and the XUV field generated is an atto-second pulse train with harmonic components nω, with odd-n only. In this case, if the intensity of the IR field is low to moderate, the resultant photoelectron spectrum will be comprised of discrete bands corresponding to direct 1-photon XUV ionization, * paul.hockett@nrc.ca and sidebands corresponding to 2-photon XUV+IR transitions [1]. (The energetics of this situation are illustrated in fig. 1.) Temporally, if the XUV pulses are short relative to the IR field cycle, the sidebands will also show significant time-dependence, since they will be sensitive to the optical phase difference between the XUV and IR fields, with an oscillatory frequency of 2ω. In this case, a measurement which is angle-integrated, or made at a single detection geometry, can be viewed as a means to characterising the properties of the XUV pulses (spectral content and optical phase), provided that the ionizing system is simple or otherwise well-characterised [1]; RABBIT can therefore be utilised as a pulse metrology technique [1,2], and this is the typical usage.Conversley, RABBIT can also be regarded as a photoelectron metrology technique, since it is sensitive to the magnitudes and phases of the various photoionization pathways accessed. In contrast to most traditional (energy-resolved) photoelectron spectroscopy techniques, RABBIT has the distinction of interfering pathways resulting from different 1-photon transition energies: it is thus sensitive to the energy-dependence of the photoionization dynamics, as well as to the partial-wave components within each pathway. An angle-resolved (AR) RABBIT measurement is particularly powerful in this regard, since the partial-wave phases are encoded in the angular part of the photoelectron interferogram. Although this is a potentially powerful technique, the underlying photoionization dynamics may be extremely complicated, hence quantitati...

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“…However, as is clear from our section 3, and the online material referred to in section 3 4 , the dipole matrix elements are included. In fact, in the additional work cited by Baykusheva and Wörner [3], they use the same software suite as we do to perform the photoionization calculations, namely ePolyScat [4][5][6], which is well-tested for photoionization problems and clearly contains the complete canonical photoionization physics [7]. Furthermore, without the transition dipole matrix elements, our results (e.g.…”

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confidence: 99%