Ab initio calculation of the photoionization cross sections and photoelectron angular distribution parameters of CH4, NH3, H2O and CO

Novikovskiy, N. M.; Sukhorukov, V. L.; Artemyev, A. N.; Demekhin, Ph. V.

doi:10.1140/epjd/e2019-90628-8

Cited by 10 publications

(24 citation statements)

References 63 publications

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“…19, did not use B-splines (which ensure a significantly improved description of the continuum), and also only included continuum partial waves up to = 4. Finally, the single-center calculations of Novikovskiy et al [60] seem to show better agreement with experiment at higher energies for the second and third states of H 2 O + . In contrast to photoionization calculations for CO 2 [37] and NO 2 [36], partial waves beyond = 4 do not contribute significantly to photoionization of water at energies below 50 eV, most likely due to the location of the oxygen atom with p-type valence orbitals close to the center of mass; s and d partial waves then constitute the dominant contribution to photoionization into the low-lying valence states of H 2 O + .…”

Section: B Single-photon Ionizationmentioning

confidence: 73%

“…When smoothed, the cross section in this region shows clearly a nonphysical energy dependence: On the one hand, the sharp steplike character will, in reality, be smoothed by the vibrational motion; on the other hand, some effect due to the closely spaced resonances might be visible in the physical cross section. Figure 4(b) shows the comparison between the RMT results and the one-photon time-independent results from Truesdale et al [73] Stener et al [59] Toffoli and Decleva [74] Novikovskiy et al [60] Banna et al [68] FIG. 6.…”

Section: B Single-photon Ionizationmentioning

confidence: 97%

“…Time-dependent calculations for H 2 O were performed in the single-active-electron approximation [54,55], strongfield approximation [56], recently using a time-dependent configuration-interaction singles approach [57], and the coupled-cluster method [17]; time-independent calculations have been performed using several approaches [58][59][60] including a recent GTO-only R-matrix one [61].…”

Section: Photoionization Of H 2 Omentioning

confidence: 99%

“…Tan et al [72] Brion and Carnovale [69] Banna et al [68] Truesdale et al [73] Novikovskiy et al [60] Modak and Antony [61] Engin et al [70] FIG. 5.…”

Section: A Characteristics Of the Calculationmentioning

confidence: 99%

“…The transitions to the three lowest states of H 2 O + are shown. Experimental data are from Tan et al [72], Truesdale et al [73], Brion and Carnovale [69], and Banna et al [68] and calculations are from Engin et al [70], Novikovskiy et al [60], and Modak and Antony [61]. The UKRmol+ results for energies smaller than 20 eV are heavily influenced by smoothing.…”

Section: A Characteristics Of the Calculationmentioning

confidence: 99%

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Perturbative and nonperturbative photoionization of H2 and H2O using the molecular R<

et al. 2020

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The ab initio R-matrix with time method has recently been extended to allow simulation of fully nonperturbative multielectron processes in molecules driven by ultrashort arbitrarily polarized strong laser fields. Here we demonstrate the accuracy and capabilities of the current implementation of the method for two targets: We study single-photon and multiphoton ionization of H 2 and one-photon and strong-field ionization of H 2 O and compare the results to available experimental and theoretical data as well as our own time-independent R-matrix calculations. We obtain a highly accurate description of total and state-to-state single-photon ionization of H 2 O and, using a simplified coupled-channel model, we show that state coupling is essential to obtain qualitatively correct results and that its importance as a function of laser intensity changes. We find that electron correlation plays a more important role at low intensities (up to approximately 50 TW/cm 2).

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Section: B Single-photon Ionizationmentioning

confidence: 73%

Section: B Single-photon Ionizationmentioning

confidence: 97%

Section: Photoionization Of H 2 Omentioning

confidence: 99%

“…Tan et al [72] Brion and Carnovale [69] Banna et al [68] Truesdale et al [73] Novikovskiy et al [60] Modak and Antony [61] Engin et al [70] FIG. 5.…”

Section: A Characteristics Of the Calculationmentioning

confidence: 99%

Section: A Characteristics Of the Calculationmentioning

confidence: 99%

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Perturbative and nonperturbative photoionization of H2 and H2O using the molecular R<

et al. 2020

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A complex Gaussian approach to molecular photoionization

2021

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We develop and implement a Gaussian approach to calculate partial cross-sections and asymmetry parameters for molecular photoionization. Optimal sets of complex Gaussian-type orbitals (cGTOs) are first obtained by nonlinear optimization, to best fit sets of Coulomb or distorted continuum wave functions for relevant orbital quantum numbers. This allows us to represent the radial wavefunction for the outgoing electron with accurate cGTO expansions. Within a time-independent partial wave approach, we show that all the necessary transition integrals become analytical, in both length and velocity gauges, thus facilitating the numerical evaluation of photoionization observables. Illustrative results, presented for NH 3 and H 2 O within a oneactive-electron monocentric model, validate numerically the proposed strategy based on a complex Gaussian representation of continuum states.

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Aqueous Ammonium Nitrate Investigated Using Photoelectron Spectroscopy of Cylindrical and Flat Liquid Jets

Gallo,

Michailoudi,

Valerio

et al. 2024

J. Phys. Chem. B

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Ammonium nitrate in aqueous solution was investigated with synchrotron radiation based photoelectron spectroscopy using two types of liquid jet nozzles. Electron emission from a cylindrical microjet of aqueous ammonium nitrate solution was measured at two different angles relative to the horizontal polarization of the incident synchrotron radiation, 90°a nd 54.7°(the "magic angle"), for a range of photon energies (470−530 eV). We obtained β parameter values as a function of photon energy, based on a normalization procedure relying on simulations of background intensity with the SESSA (Simulation of Electron Spectra for Surface Analysis) package. The β values are similar to literature data for O 1s ionization of liquid water, and the β value of N 1s from NH 4 + is higher than that for NO 3 − , by ≈0.1. The measurements also show that the photoelectron signal from NO 3 − exhibits a photon energy dependent cross section variation not observed in NH 4 + . Additional measurements using a flat jet nozzle found that the ammonium and nitrate peak area ratio was unaffected by changes in the takeoff angle, indicating a similar distribution of both ammonium and nitrate in the surface region.

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Ab initio calculation of the photoionization cross sections and photoelectron angular distribution parameters of CH4, NH3, H2O and CO

Cited by 10 publications

References 63 publications

Perturbative and nonperturbative photoionization of H2 and H2O using the molecular R<

Perturbative and nonperturbative photoionization of H2 and H2O using the molecular R<

A complex Gaussian approach to molecular photoionization

Aqueous Ammonium Nitrate Investigated Using Photoelectron Spectroscopy of Cylindrical and Flat Liquid Jets

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