Electron impact excitation of helium: A ploarization correlation study of the 3{sup 1}P state at 40 eV incident energy

Journal Article · Wed May 01 04:00:00 EDT 1996 · Bulletin of the American Physical Society

OSTI ID:394135

Harris, C L; Dorio, L A; Neill, P A ^[1]

---

1. Univ. of Nevada, Reno, NV (United States)

Recently the Convergent Close-Coupling calculations, (CCC), of Fursa and Bray have been very successful predicting the behavior of the electron impact coherence parameters (EICP) for electron impact excitation of helium. In the present experimental study the linear Stokes parameters P{sub 1} and P{sub 2} have been measured for He(3{sup 1}P) excitation using the polarization correlation technique. Data will be presented for electron impact energies of 40eV and 50eV. At present no other experimental data is available at 40eV. At 50eV angular correlation data measured using the VUV 3{sup 1}P-1{sup 1}S photons are available only out to a maximum electron scattering angle of 85{degrees}. Due to the disadvantageous differential cross section and 40:1 branching ratio in favor of the VUV decay, the uncertainties in the present data are large. However, at selected electron scattering angles they are sufficient to distinguish the lack of convergence of the CCC predictions for the 69 state calculations (CCC69) in comparison with the 75 state model (CCC75). In particular at 50 eV incident electron energy and 120{degrees} scattering angle the charge cloud alignment angles predicted by the two calculations differ by 90{degrees}.

• OSTI ID: 394135
• Report Number(s): CONF-9605105--
• Journal Information: Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 3 Vol. 41; ISSN BAPSA6; ISSN 0003-0503
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
CALCULATION METHODS
COULOMB EXCITATION
ELECTRON-ATOM COLLISIONS
EV RANGE 10-100
HELIUM
P STATES
POLARIZATION