We report absolute measurements at a rank four state multipole for He(3 1D) excitation by electron impact with a polarized first-photon-second-photon coincidence technique. The presented technique permits the extraction of total (scattering angle integrated) partial cross sections σm for the excitation of He(3 1Dm) magnetic substates (m=0,±1,±2). The present results stringently test existing theories and, for example, indicate that most theoretical calculations underestimate the partial cross sections σ0 and σ1 and overestimate the σ2. The recent convergent close-coupling calculations of Fursa and Bray [Phys. Rev. A 52, 1279 (1995)] are in excellent agreement with all our measured data.
|Number of pages||8|
|Journal||Physical Review A - Atomic, Molecular, and Optical Physics|
|Publication status||Published - May 1996|