Electron doubly differential cross section for 0. 5-MeV H/sup -/-He detachment collisions

Journal Article · Thu Feb 28 23:00:00 EST 1985 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.31.1336· OSTI ID:5923310

Park, C; Starace, A F; Macek, J

A comprehensive theoretical treatment is presented for the electron detachment cross section, differential in both electron momentum and direction, for collisions of 0.5-MeV H/sup -/ projectiles on He targets. Our calculation, which assumes that the residual H atom is left in the 1s state, employs the usual first Born approximation as well as the closure approximation (in order to sum over all He target final states). Electron correlations within the H/sup -/ system are treated in detail within the framework of the adiabatic hyperspherical coordinate approximation. In particular, for the first time for this collision process, angular correlations are included. The s, p, and d partial-wave components of the detached electron hyperspherical coordinate wave function are also included. The helium target is described by the atomic form factor and the incoherent scattering function tabulated by Hubbell et al. as well as by an average He excitation energy, I-bar/sub He/. The prescription of Lee and Chen for I-bar/sub He/, which for small scattering angles gives the value 35 eV is found to result in the best agreement of our calculated doubly differential cross sections with experiment, both in shape and in predicted peak energies. The unique feature of the experimental doubly differential detachment cross section of Menendez and Duncan, that for electron-scattering angles less than 4/sup 0/ there is a double peak, is reproduced in our calculations. However, the predicted higher-energy peak is smaller in magnitude and higher in energy than that observed experimentally. This difference is attributed to the influence of excited H-atom states, which are measured in the experiments.

• Research Organization: Department of Physics and Astronomy, The University of Nebraska, Lincoln, Nebraska 68588-0111
• OSTI ID: 5923310
• Journal Information: Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 31:3; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ANIONS
ATOM COLLISIONS
BORN APPROXIMATION
CHARGED PARTICLES
COLLISIONS
CORRELATIONS
CROSS SECTIONS
DIFFERENTIAL CROSS SECTIONS
ELECTRON CORRELATION
ELECTRON DETACHMENT
ELEMENTS
ENERGY RANGE
FLUIDS
FORM FACTORS
GASES
HELIUM
HYDROGEN IONS
HYDROGEN IONS 1 MINUS
ION COLLISIONS
ION-ATOM COLLISIONS
IONS
KEV RANGE
KEV RANGE 100-1000
NONMETALS
PARTIAL WAVES
PARTICLE PROPERTIES
RARE GASES