scholarly journals Rosetta Mission: Electron Scattering Cross Sections—Data Needs and Coverage in BEAMDB Database

2017 ◽  
Author(s):  
Bratislav P. Marinković ◽  
Jan Hendrik Bredehöft ◽  
Veljko Vujčić ◽  
Darko Jevremović ◽  
Nigel J. Mason
Keyword(s):  
Electron Impact ◽  
Electron Scattering ◽  
Cross Sections ◽  
Molecular Data ◽  
Scattering Data ◽  
Particle Analysis ◽  
Detailed Knowledge ◽  
Molecular Systems ◽  
Rosetta Mission

The emission of [O I] lines in the coma of Comet 67P/Churyumov-Gerasimenko during the Rosetta mission have been explained by electron impact dissociation of water rather than the process of photodissociation. This is the direct evidence for the role of electron induced processing has been seen on such a body. Analysis of other emission features is handicapped by a lack of detailed knowledge of electron impact cross sections which highlights the need for a broad range of electron scattering data from the molecular systems detected on the comet. In this paper we present an overview of the needs for electron scattering data relevant for the understanding of observations in coma, the tenuous atmosphere and on the surface of 67P/Churyumov-Gerasimenko during the Rosetta mission. The relevant observations for elucidating the role of electrons come from optical spectra, particle analysis using the ion and electron sensors and mass spectrometry measurements. To model these processes electron impact data should be collated and reviewed in an electron scattering database and an example is given in the BEAMD, which is a part of a larger consortium of Virtual Atomic and Molecular Data Centre – VAMDC.

scholarly journals Rosetta Mission: Electron Scattering Cross Sections - Data Needs and Coverage in BEAMDB Database

2017 ◽  
Author(s):  
Bratislav P. Marinković ◽  
Jan Hendrik Bredehöft ◽  
Veljko Vujčić ◽  
Darko Jevremović ◽  
Nigel J. Mason
Keyword(s):  
Electron Impact ◽  
Electron Scattering ◽  
Cross Sections ◽  
Molecular Data ◽  
Scattering Data ◽  
Particle Analysis ◽  
Detailed Knowledge ◽  
Molecular Systems ◽  
Rosetta Mission

The emission of [O I] lines in the coma of Comet 67P/Churyumov-Gerasimenko during the Rosetta mission have been explained by electron impact dissociation of water rather than the process of photodissociation. This is the direct evidence for the role of electron induced processing has been seen on such a body. Analysis of other emission features is handicapped by a lack of detailed knowledge of electron impact cross sections which highlights the need for a broad range of electron scattering data from the molecular systems detected on the comet. In this paper we present an overview of the needs for electron scattering data relevant for the understanding of observations in coma, the tenuous atmosphere and on the surface of 67P/Churyumov-Gerasimenko during the Rosetta mission. The relevant observations for elucidating the role of electrons come from optical spectra, particle analysis using the ion and electron sensors and mass spectrometry measurements. To model these processes electron impact data should be collated and reviewed in an electron scattering database and an example is given in the BEAMD, which is a part of a larger consortium of Virtual Atomic and Molecular Data Centre – VAMDC.

scholarly journals Role of Negative Ion Resonances in Electron Scattering from Atoms and Molecules

1999 ◽  
Vol 52 (3) ◽  
pp. 473 ◽  
Author(s):  
S. J. Buckman ◽  
D. T. Alle ◽  
M. J. Brennan ◽  
P. D. Burrow ◽  
J. C. Gibson ◽  
...  
Keyword(s):  
Electron Scattering ◽  
Cross Sections ◽  
Negative Ions ◽  
Negative Ion ◽  
Electron Correlations ◽  
Molecular Systems ◽  
Atoms And Molecules ◽  
Wide Range ◽  
Scattering Cross Sections

Transient negative ions (resonances) formed during the collision of an electron with an atom or molecule have been extensively studied for over thirty years. The continued interest in these states, both experimentally and theoretically, stems from the profound effects that they can have on electron scattering cross sections and the role that electron–electron correlations play in their formation and quasi-stability. A selective discussion of examples of such resonances, involving one, two and three excited electrons is given for a wide range of atomic and molecular systems.

scholarly journals Few Body Effects in the Electron and Positron Impact Ionization of Atoms

Atoms ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 33
Author(s):  
R.I. Campeanu ◽  
Colm T. Whelan
Keyword(s):  
Electron Impact ◽  
Cross Sections ◽  
Differential Cross ◽  
Impact Ionization ◽  
Inert Gas ◽  
Interference Effects ◽  
Positron Impact ◽  
Competing Interactions ◽  
Energy Sharing

Triple differential cross sections (TDCS) are presented for the electron and positron impact ionization of inert gas atoms in a range of energy sharing geometries where a number of significant few body effects compete to define the shape of the TDCS. Using both positrons and electrons as projectiles has opened up the possibility of performing complementary studies which could effectively isolate competing interactions that cannot be separately detected in an experiment with a single projectile. Results will be presented in kinematics where the electron impact ionization appears to be well understood and using the same kinematics positron cross sections will be presented. The kinematics are then varied in order to focus on the role of distortion, post collision interaction (pci), and interference effects.

Calculation of gas-kinetic radius and van der Waals coefficient from electron scattering cross-sections

2021 ◽  
pp. 82-86
Author(s):  
Akash Kumar ◽  
Biplab Goswami
Keyword(s):  
Gas Phase ◽  
Electron Impact ◽  
Electron Scattering ◽  
Cross Sections ◽  
Analytical Approach ◽  
Van Der Waals ◽  
Scattering Cross ◽  
Environmentally Sensitive ◽  
Scattering Cross Sections ◽  
Good Agreement

The gas-kinetic radius (r) and van der Waals coefficient (b) are two usable quantities for characterizing the motion of any molecules in the gas phase. In this article, comprehensive calculations of r and b of various environmentally sensitive molecules like SF6, NF3, GeF4, Si2H6 and Cl2O are reported. In the present study, an analytical approach for calculations of r and b was used from the electron impact cross-sections data of these molecules. In general, the reported values of r and b shows good agreement with the previous theories and experiments.

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