Angular distribution of low-energy electron emission in collisions of 6-MeV/u bare carbon ions with molecular hydrogen: Two-center mechanism and interference effect

Misra, Deepankar; Kelkar, Aditya H.; Kadhane, U.; Kumar, Ajay; Singh, Yeshpal; Tribedi, Lokesh C.; Fainstein, P D

doi:10.1103/physreva.75.052712

Cited by 46 publications

(50 citation statements)

References 38 publications

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“…3, discussed earlier) does not show any oscillation as a function of the electron velocity. However, this also is in contrast to the earlier result for H 2 , wherein a prominent oscillatory behavior was observed in the the velocity dependence of the α parameter [7]. This particular phenomenon in the case of H 2 is well understood in terms of the double-slit interference in the case of diatomic molecules.…”

Section: Asymmetry Parametercontrasting

confidence: 55%

“…This is qualitatively reproduced by the CDW-EIS model although it overestimates the data. This is, however, different from the behavior observed in the cases of H 2 and He, where a peak around 75 • in the DDCS angular distribution was observed at emission energy as low as 15 eV [7,35].…”

Section: A Energy Distributions Of the Electron Ddcss At Definite Emcontrasting

confidence: 44%

“…These distributions are in large disagreement with the calculations predicted from the first-order Born approximation. Several theoretical [1,2] and experimental [3][4][5][6][7] studies indicate the success of the quantum-mechanical models based on continuum distorted-wave approximations. Double-differential cross section (DDCS) studies of low-energy electrons emitted in ionization of medium-Z atoms and molecules by different projectiles have been reported in a few cases [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

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Impact ionization of molecular oxygen by 3.5-MeV/u bare carbon ions

et al. 2012

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We have measured the absolute double-differential cross sections (DDCSs) for electron emission in ionization of O 2 molecules under the impact of 3.5-MeV/u C 6+ ions. The data were collected between 10 and 600 eV, in an angular range of 30 • to 150 • . The single-differential cross sections (SDCSs) in emission angle and electron energy are deduced from the electron DDCS spectra. Also, the total cross section has been obtained from the SDCS spectra. The DDCS spectra as well as the SDCS spectra are compared with continuum distorted-wave eikonal initial-state calculations which employ molecular wave functions built as linear combinations of atomic orbitals. The DDCS ratio i.e. σ O2 /2σ O , derived by dividing the experimental DDCS for molecular oxygen with the theoretical DDCS for atomic oxygen, does not show any primary or secondary oscillations arising from Young-type interference, which is apparently in contrast to what has been observed earlier for H 2 and in agreement with the model calculation. Similarly, the forward-backward angular asymmetry increases monotonically with the velocity of the emitted electrons. However, the results on the DDCSs, SDCSs, the asymmetry parameter, and the nonexistence of oscillations are in qualitative agreement with the predictions of the model used.

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Section: Asymmetry Parametercontrasting

confidence: 55%

Section: A Energy Distributions Of the Electron Ddcss At Definite Emcontrasting

confidence: 44%

Section: Introductionmentioning

confidence: 99%

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Impact ionization of molecular oxygen by 3.5-MeV/u bare carbon ions

et al. 2012

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“…For dressed projectiles, multiple electron scattering at lower energies [9][10][11][12][13] and dielectronic (antiscreening) effects [33] at higher energies may also provide observable contributions to the spectra. Strong angular asymmetries due to two-or many-center effects are also expected in the studied energy region [21,23,25,34]. Altogether, in the actual energy and projectile charge-state region of the present study, a full treatment of the whole ion-molecule collision scenario represents a challenge for collision theories.…”

Section: Introductionmentioning

confidence: 99%

“…100 MeV. Ionization by bare ions was investigated in detail by Tribedi and co-workers for a wide range of targets with emphasis on the two-center (TCE) and interference effects [21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Ionization of small molecules induced byH+, He+, and
Kovács
¹
,
Herczku
²
,
Juhász
³

et al. 2016
Phys. Rev. A

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We report the energy and angular distribution of ejected electrons from CH 4 and H 2 O molecules impacted by 1 MeV H + , He + , and 650 keV N + ions. Spectra were measured at different observation angles, from 2 to 2000 eV. The obtained absolute double-differential electron-emission cross sections (DDCSs) were compared with the results of classical trajectory Monte Carlo (CTMC) and continuum distorted wave, eikonal initial state (CDW-EIS) calculations. For the bare H + projectile both theories show remarkable agreement with the experiment at all observed angles and energies. The CTMC results are in similarly good agreement with the DDCS spectra obtained for impact by dressed He + and N + ions, where screening effects and electron loss from the projectile gain importance. The CDW-EIS calculations slightly overestimate the electron loss for 1 MeV He + impact, and overestimate both the target and projectile ionization at low emitted electron energies for 650 keV N + impact. The contribution of multiple electron scattering by the projectile and target centers (Fermi shuttle) dominates the N + -impact spectra at higher electron energies, and it is well reproduced by the nonperturbative CTMC calculations. The contributions of different processes in medium-velocity collisions of dressed ions with molecules are determined.

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Fragmentation of positronium in collision with Li ion including electron loss to the continuum

Roy

Sinha

2009

Pramana - J Phys

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Fragmentation of ground state ortho-positronium (Ps) in collision with Li ion (Li + ) is studied in the framework of post-collisional Coulomb distorted eikonal approximation (CDEA), giving special emphasis on the dynamics of the electron loss to the continuum (ELC) that occurs when the electron (e) and the positron (e + ) are very close to each other in the velocity space (v e ≈ vp). The present model takes account of the two-centre effect on the ejected e which is crucial for a proper description of the ELC phenomena. Both the fully differential cross-section (TDCS) and the doubly differential cross-section (DDCS) (energy spectra) are investigated at intermediate and high incident energies. A broad distinct ELC peak centred around ve ≈ vp is noted in the e energy spectrum in contrast to the sharp ELC peak for a heavy projectile, corroborating the experimental findings. Two salient features are noted in the present study: (i) the shift of the e DDCS peak (summed over e + angles) towards higher ejection energy with respect to half the residual energy of the system, (ii) comparison of the e and e + energy spectra reflect a strong e-e + asymmetry with respect to the ratio ve/vp = 1. Both these features are in qualitative agreement with the experimental observations due to Armitage et al for Ps-He atom system and could be attributed to the post-collisional two-centre effect on e due to its parent nucleus (e + ) and the screened target ion. Two different wave functions of the Li ion are chosen in order to test the sensitivity of the present results with respect to the choice of the wave function.

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Angular distribution of low-energy electron emission in collisions of 6-MeV/u bare carbon ions with molecular hydrogen: Two-center mechanism and interference effect

Cited by 46 publications

References 38 publications

Impact ionization of molecular oxygen by 3.5-MeV/u bare carbon ions

Impact ionization of molecular oxygen by 3.5-MeV/u bare carbon ions

Ionization of small molecules induced byH+, He+, and
Kovács
¹
,
Herczku
²
,
Juhász
³

et al. 2016
Phys. Rev. A

Fragmentation of positronium in collision with Li ion including electron loss to the continuum

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Angular distribution of low-energy electron emission in collisions of 6-MeV/u bare carbon ions with molecular hydrogen: Two-center mechanism and interference effect

Cited by 46 publications

References 38 publications

Impact ionization of molecular oxygen by 3.5-MeV/u bare carbon ions

Impact ionization of molecular oxygen by 3.5-MeV/u bare carbon ions

Ionization of small molecules induced byH+, He+, andKovács1, Herczku2, Juhász3 et al. 2016Phys. Rev. A

Fragmentation of positronium in collision with Li ion including electron loss to the continuum

Contact Info

Product

Resources

About

Ionization of small molecules induced byH+, He+, and
Kovács
¹
,
Herczku
²
,
Juhász
³

et al. 2016
Phys. Rev. A