scholarly journals The role of high Rydberg states in the generation of negative ions in negative-ion discharges

1996 ◽  
Author(s):  
J. R. Hiskes
Keyword(s):  
Rydberg States ◽  
Negative Ions ◽  
Negative Ion

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.

Cassini CAPS-ELS Observations of Negative Ions in Titan's Ionosphere: Solar Zenith Angle - Density Trends

2021 ◽  
Author(s):  
Anne Wellbrock ◽  
Andrew Coates ◽  
Geraint Jones ◽  
Richard Haythornthwaite ◽  
Oleg Shebanits ◽  
...  
Keyword(s):  
Zenith Angle ◽  
Solar Zenith Angle ◽  
Electron Attachment ◽  
Negative Ions ◽  
Negative Ion ◽  
Unexpected Result ◽  
Cassini Mission ◽  
Haze Formation

<p>The discovery of heavy organic anions by in situ measurements using Cassini’s CAPS Electron Spectrometer (ELS) in Titan’s ionosphere was an unexpected result of the Cassini mission (Coates et al, 2007, Waite et al, 2007); a complete reconsideration of chemical processes in this enigmatic atmosphere was necessary as a result. These negative ions can be associated with complex hydrocarbon and nitrile processes which are linked to haze formation at lower altitudes. Cassini’s CAPS ELS observed negative ions during Titan encounters at altitudes below 1400 km. The ions can reach masses over 13,000 amu/q (Coates et al., 2009), while recurring peaks in the mass spectra can be used to identify different mass groups as reported by Coates et al. (2007) and Wellbrock et al. (2013, 2019). Studying density and mass trends of these groups helps to identify controlling factors of the production and destruction mechanisms, and ultimately to improve our understanding of how organic macromolecules can be produced by naturally occurring abiotic processes. In this study we examine the effects different solar zenith angle conditions might have on both the light and heavy negative ion mass groups, and consider the role of processes such as photodetachment and dissociative electron attachment. We also compare the negative ion data with RPWS electron measurements and discuss the possible implications associated with the above processes.</p>

Carbon Nitride Film Formation by Low Energy Positive and Negative Ion Beam Deposition

1996 ◽  
Vol 438 ◽  
Author(s):  
N. Tsubouchi ◽  
Y. Horino ◽  
B. Enders ◽  
A. Chayahara ◽  
A. Kinomura ◽  
...  
Keyword(s):  
Carbon Nitride ◽  
Rutherford Backscattering Spectrometry ◽  
Ion Beam ◽  
High Vacuum ◽  
Negative Ions ◽  
Low Energy ◽  
Ultra High Vacuum ◽  
Negative Ion ◽  
Nitride Film ◽  
Ion Energy

AbstractUsing a newly developed ion beam apparatus, PANDA (Positive And Negative ions Deposition Apparatus), carbon nitride films were prepared by simultaneous deposition of mass-analyzed low energy positive and negative ions such as C2-, N+, under ultra high vacuum conditions, in the order of 10−6 Pa on silicon wafer. The ion energy was varied from 50 to 400 eV. The film properties as a function of their beam energy were evaluated by Rutherford Backscattering Spectrometry (RBS), Fourier Transform Infrared spectroscopy (FTIR) and Raman scattering. From the results, it is suggested that the C-N triple bond contents in films depends on nitrogen ion energy.

The role of high Rydberg states in enhanced O-formation in a pulsed O2discharge

1999 ◽  
Vol 8 (3) ◽  
pp. 384-391 ◽  
Author(s):  
W X Ding ◽  
L A Pinnaduwage ◽  
C Tav ◽  
D L McCorkle
Keyword(s):  
Rydberg States

scholarly journals Single-Photon Multiple Detachment in Fullerene Negative Ions: Absolute Ionization Cross Sections and the Role of the Extra Electron

2013 ◽  
Vol 111 (4) ◽  
Author(s):  
R. C. Bilodeau ◽  
N. D. Gibson ◽  
C. W. Walter ◽  
D. A. Esteves-Macaluso ◽  
S. Schippers ◽  
...  
Keyword(s):  
Cross Sections ◽  
Single Photon ◽  
Negative Ions ◽  
Ionization Cross ◽  
Extra Electron ◽  
Ionization Cross Sections

Note on radiationless transitions involving three-body collisions

1936 ◽  
Vol 32 (3) ◽  
pp. 482-485 ◽  
Author(s):  
R. A. Smith
Keyword(s):  
Continuous Spectrum ◽  
Negative Ions ◽  
Bound State ◽  
Excess Energy ◽  
Negative Ion ◽  
Positive Ions ◽  
Continuous State ◽  
Direct Formation ◽  
Three Body ◽  
Positive Ion

When an electron makes a transition from a continuous state to a bound state, for example in the case of neutralization of a positive ion or formation of a negative ion, its excess energy must be disposed of in some way. It is usually given off as radiation. In the case of neutralization of positive ions the radiation forms the well-known continuous spectrum. No such spectrum due to the direct formation of negative ions has, however, been observed. This process has been fully discussed in a recent paper by Massey and Smith. It is shown that in this case the spectrum would be difficult to observe.

Chaos in positive ion–negative ion magnetized plasmas

2020 ◽  
Vol 86 (6) ◽  
Author(s):  
Samiran Ghosh ◽  
Biplab Maity ◽  
Swarup Poria
Keyword(s):  
Nonlinear Wave ◽  
Low Frequency ◽  
Negative Ions ◽  
Dynamical Behaviour ◽  
Negative Ion ◽  
Sound Waves ◽  
Weakly Nonlinear ◽  
Positive Ions ◽  
Experimental Parameters ◽  
Map Analysis

The dynamical behaviour of weakly nonlinear, low-frequency sound waves are investigated in a plasma composed of only positive and negative ions incorporating the effects of a weak external uniform magnetic field. In the plasma model the mass (temperature) of the positive ions is smaller (larger) than that of the negative ions. The dynamics of the nonlinear wave is shown to be governed by a novel nonlinear equation. The stationary plane wave (analytical and numerical) nonlinear analysis on the basis of experimental parameters reveals that the nonlinear wave does have quasi-periodic and chaotic solutions. The Poincarè return map analysis confirms these observed complex structures.

scholarly journals Some aspects of ion-acoustic whistlers in the ionosphere in the presence of negative ions

1989 ◽  
Vol 12 (4) ◽  
pp. 749-772 ◽  
Author(s):  
A. K. Sur ◽  
G. C. Das ◽  
B. Chakraborty ◽  
S. N. Paul ◽  
L. Debnath
Keyword(s):  
Travel Time ◽  
Critical Frequency ◽  
Cyclotron Frequency ◽  
Negative Ions ◽  
Induced Magnetic Field ◽  
Ion Acoustic ◽  
Phase And Group Velocities ◽  
Group Velocities ◽  
Group Travel

A study is made of the propagation of ion-acoustic whistlers in the atmosphere including the effects of negative ions. The dispersion relation, phase and group velocities of whistlers are discussed. It is shown that the presence of negative ions introduces a critical frequency which, for equal ionic masses, is equal to the ion-cyclotron frequency. Special attention is given to the group travel time of whistlers at mid-latitude and equator so that the role of negative ions on the group travel time can be determined. The cyclotron damping of whistlers in the presence of negative ions has been studied. The velocity distribution, total attenuation and the induced magnetic field are calculated from the temporal as well as spatial cyclotron damping. It is suggested that the attenuation of whistlers may cause heating of the ionosphere. It is also indicated that the measurement of the group travel time from its source to the observer at the satellite would help to diagnose the ionospheric parameters. The results of the analysis are presented by several graphical presentations.

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