The separable representation of exchange in electron scattering from polyatomic targets

Čurík, Roman; Gianturco, F. A.; Sanna, Nico

doi:10.1088/0953-4075/33/14/307

Cited by 32 publications

(25 citation statements)

References 23 publications

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“…We are using a modified version of the VOLPOS program package [65] for the single-centre-expansion of the electron densities, for the construction of the potential and the solution of the scattering equations by Volterra integration. In all calculations the radial grid was extended up to a distance of 146 bohr.…”

Section: Quantum Scattering Calculationsmentioning

confidence: 99%

Positron-electron correlation-polarization potentials for the calculation of positron collisions with atoms and molecules*

Franz

2017

Eur. Phys. J. D

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Abstract. We present correlation-polarization potentials for the calculation of scattering cross sections of positrons with atoms and molecules. The potentials are constructed from a short-range correlation term and a long-range polarization term. For the short-range correlation term we present four different potentials that are derived from multi-component density functionals. For the long-range polarization term we employ a multi-term expansion. Quantum scattering calculations are presented for low energy collisions of positrons with two atomic targets (argon and krypton) and two molecular targets (nitrogen and methane). For collision energies below the threshold for Positronium formation our calculations of scattering cross sections are in good agreement with recent data sets from experiments and theory.

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Section: Quantum Scattering Calculationsmentioning

confidence: 99%

Positron-electron correlation-polarization potentials for the calculation of positron collisions with atoms and molecules*

Franz

2017

Eur. Phys. J. D

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“…The single-centre-expansions (SCE) of the molecular electron density and of the potential are computed with the VOLPOS software package [49], which is also used to solve the coupled scattering equations by Volterra integration. The grid for the radial integration ranges up to distance of 146 bohr.…”

Section: Quantum Scattering Calculationsmentioning

confidence: 99%

Do positrons measure atomic and molecular diameters?

2016

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Abstract. We report on density functional calculations (DFT) of elastic integral scattering cross-sections for positron collisions with argon, krypton, nitrogen and methane. The long-range asymptotic polarization potential is described using higher-order terms going much beyond an induced dipole potential (−α/r 4 ) while the short-range interaction is modeled by two different forms of electron -positron correlation potential (Boroński-Nieminen and Quantum Monte Carlo potentials). The results of both approaches agree quite well with the recent theoretical and measured values. Based on the present and previous theoretical and experimental data we discuss some systematics observed in integral scattering cross-sections below the positronium formation threshold. In particular we point out on the correlation between the values of scattering cross-sections and atomic dimensions.

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“…(6) under the boundary conditions that the asymptotic form of u lv is represented by a sum containing outgoing spherical Bessel and Neumann functions we obtain the corresponding S-matrix elements S lv l v . The actual numerical procedure we have employed to solve that equation is given in detail in [11,12].…”

Section: A Scattering Equationsmentioning

confidence: 99%

Low-energy positron scattering from gas-phase pyrimidine: A quantum treatment of the dynamics and a comparison with experiments

Franz

Gianturco

2013

Phys. Rev. A

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In the present work we are reporting detailed quantum scattering calculations that describe the diffusion of a beam of low-energy positrons interacting with the pyrimidine target as a gas-phase partner. The calculations have employed an essentially ab initio model for the short-range correlation interaction and for the electrostatic interaction of an impinging positron and the electron+nuclear structure of the target molecule at its equilibrium geometry. The available experiments were also performed in the low-energy region below about 30 eV and have been reported by two different experimental groups cited in the main text. Those data include integral elastic plus rotationally and vibrationally summed cross sections, together with angular distributions over the same range of energies. The effects on the scattering observables which stem from the permanent dipole moment of the title molecule are carefully analyzed and computational corrections which ensure numerical convergence are introduced and discussed. The additional uncertainties introduced by the angular discrimination error present in the experiments are also discussed and analyzed, thereby providing a numerical procedure for correcting all available data. The final comparison between experimental angular distributions and the computed counterparts produced in the present work turns out to be very good. The same applies to the comparison in size and energy dependence of the integral cross sections, where we show that our calculated quantities and the corrected experiments are in very good agreement over the whole range of available energies.

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The separable representation of exchange in electron scattering from polyatomic targets

Cited by 32 publications

References 23 publications

Positron-electron correlation-polarization potentials for the calculation of positron collisions with atoms and molecules*

Positron-electron correlation-polarization potentials for the calculation of positron collisions with atoms and molecules*

Do positrons measure atomic and molecular diameters?

Low-energy positron scattering from gas-phase pyrimidine: A quantum treatment of the dynamics and a comparison with experiments

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