Total-cross-section measurements for positrons and electrons colliding with H/sub 2/, N/sub 2/, and CO/sub 2/

Journal Article · Mon Mar 01 04:00:00 EST 1982 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.25.1393· OSTI ID:5651441

Hoffman, K R; Dababneh, M S; Hsieh, Y; Kauppila, W E; Pol, V; Smart, J H; Stein, T S

Total scattering cross sections have been measured in the same apparatus for positrons and electrons colliding with H/sub 2/, N/sub 2/, and CO/sub 2/ using a beam transmission technique. The projectile impact energies range from 1--500 eV for e/sup +/-H/sub 2/, 2--500 eV for e/sup -/-H/sub 2/, 0.5--750 eV for e/sup +/-N/sub 2/, 2.2--700 eV for e/sup -/-N/sub 2/, 0.5--60 eV for e/sup +/-CO/sub 2/, and 2--50 eV for e/sup -/-CO/sub 2/. The onset of positronium formation is clearly seen by an abrupt rise in the total cross sections for positrons colliding with each of the molecules at the respective positronium-formation thresholds. The positron measurements are compared with the electron measurements at intermediate energies for H/sub 2/ and N/sub 2/. This comparison reveals a merging of the cross sections for H/sub 2/ at energies above 200 eV, while for N/sub 2/ the electron results remain higher than the positron results at all energies. Estimates are made of potential experimental errors, as well as the experimental resolution for discrimination against projectiles scattered at small forward angles.

• Research Organization: Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48202
• OSTI ID: 5651441
• Journal Information: Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 25:3; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
COLLISIONS
CROSS SECTIONS
DATA
ELECTRON COLLISIONS
ELECTRON-MOLECULE COLLISIONS
ELEMENTS
ENERGY RANGE
EV RANGE
EV RANGE 01-10
EV RANGE 10-100
EV RANGE 100-1000
EXPERIMENTAL DATA
HYDROGEN
INFORMATION
MOLECULE COLLISIONS
NITROGEN
NONMETALS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
POSITRON COLLISIONS
POSITRON-MOLECULE COLLISIONS
POSITRONIUM
TOTAL CROSS SECTIONS