Spin-exchange scattering cross sections for hydrogen atoms at low temperatures

1980 ◽  
Vol 58 (6) ◽  
pp. 881-885 ◽  
Author(s):  
A. J. Berlinsky ◽  
B. Shizgal
Keyword(s):  
Cross Sections ◽  
Low Temperatures ◽  
Atomic Hydrogen ◽  
Spin Exchange ◽  
Low Energy ◽  
Energy Limit ◽  
Hydrogen Atoms ◽  
Exchange Scattering ◽  
Scattering Cross Sections

Calculations are presented of the low energy (0 < E ≤ 10−2 eV) spin exchange and frequency shift cross sections for (H,H) scattering, and of their thermal averages for 0 < T < 10 K. In particular, the behaviour of the cross sections in this low energy limit and the role of resonances due to orbiting collisions is studied in detail. A comparison is made with recent nmr measurements on gaseous atomic hydrogen at liquid helium temperatures. The results of this work suggest further useful experiments at low temperatures.

Theory of low temperature spin exchange scattering for a physisorbed two-dimensional gas of hydrogen atoms

1983 ◽  
Vol 61 (7) ◽  
pp. 1042-1045 ◽  
Author(s):  
M. Morrow ◽  
A. J. Berlinsky
Keyword(s):  
Cross Sections ◽  
Spin Exchange ◽  
Relaxation Times ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Hydrogen Atoms ◽  
Transverse Relaxation ◽  
Exchange Scattering ◽  
The One ◽  
Scattering Cross Sections

Calculations are presented of the two-dimensional scattering cross sections which are required to evaluate the longitudinal and transverse relaxation times T1 and T2 and the frequency shift Δν due to spin exchange collisions between H atoms physisorbed on a surface. The results are used to interpret the recent measurements by Crampton and co-workers of the relaxation time T1 for H atoms in the presence of solid H2 walls. New results are also presented for T1, due to three-dimensional scattering in the gas, using a more recent triplet H–H potential than the one previously employed by Berlinsky and Shizgal.

scholarly journals Сечения образования ионов He-=SUP=-+-=/SUP=- в различных электронных состояниях при столкновениях ионов He-=SUP=-2+-=/SUP=- с атомами водорода

2020 ◽  
Vol 90 (6) ◽  
pp. 895
Author(s):  
А.А. Басалаев ◽  
В.В. Кузьмичев ◽  
М.Н. Панов ◽  
О.В. Смирнов
Keyword(s):  
Kinetic Energy ◽  
Electron Capture ◽  
Cross Sections ◽  
Atomic Hydrogen ◽  
Precision Measurements ◽  
Capture Cross ◽  
Hydrogen Atoms ◽  
Hydrogen Target ◽  
Degree Of Dissociation ◽  
Capture Cross Sections

Using collision spectroscopy based on precision measurements of the kinetic energy of projectile ions that capture an electron, we measured the state selective electron capture cross sections of formation of He^+(n) ions at collision 3^He^{2 +} ions with an energy of E = 1.4-10 keV/a.m.u. with hydrogen atoms. The atomic hydrogen target with a degree of dissociation 78% at a temperature of tungsten dissociation cell 2180K has been made.

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 Anomalous enhancements of low-energy fusion rates in plasmas: the role of ion momentum distributions and inhomogeneous screening

Open Physics ◽  
2009 ◽  
Vol 7 (3) ◽  
Author(s):  
Massimo Coraddu ◽  
Marcello Lissia ◽  
Piero Quarati
Keyword(s):  
Cross Sections ◽  
Thermal Effects ◽  
Quantum Effect ◽  
Reaction Rates ◽  
Low Energy ◽  
Electron Screening ◽  
Quantum Uncertainty ◽  
Spatial Fluctuations ◽  
Theoretical Predictions

AbstractNon-resonant fusion cross-sections significantly higher than corresponding theoretical predictions are observed in low-energy experiments with deuterated matrix target. Models based on thermal effects, electron screening, or quantum-effect dispersion relations have been proposed to explain these anomalous results: none of them appears to satisfactory reproduce the experiments. Velocity distributions are fundamental for the reaction rates and deviations from the Maxwellian limit could play a central role in explaining the enhancement. We examine two effects: an increase of the tail of the target Deuteron momentum distribution due to the Galitskii-Yakimets quantum uncertainty effect, which broadens the energy-momentum relation; and spatial fluctuations of the Debye-Hückel radius leading to an effective increase of electron screening. Either effect leads to larger reaction rates especially large at energies below a few keV, reducing the discrepancy between observations and theoretical expectations.

Scattering cross sections for low-energy rare-gas + C60 and C60 + C60 collisions

1997 ◽  
Vol 270 (1-2) ◽  
pp. 121-128 ◽  
Author(s):  
A. Ruiz ◽  
J. Bretón ◽  
J.M. Gomez Llorente
Keyword(s):  
Cross Sections ◽  
Low Energy ◽  
Rare Gas ◽  
Scattering Cross ◽  
Scattering Cross Sections
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