Electron - photon polarization correlation study of the state of Ca atoms excited by electron impact

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Experimental values of the electron-impact coherence parameters (EICP) are reported for electron-impact excitation of the 4 1 P 1 state of Ca. The results have been obtained using electron-photon coincidence techniques for incident electron energies of 45 and 60 eV and scattering angles of 15 • , 20 • , 25 • , 30 • , 35 • and 40 • . EICP values determined at 45 eV are compared with similar data obtained by other groups with coincidence and optical pumping methods. Our data do not show a disagreement with the theoretical calculations based on a relativistic distorted-wave approximation (RDWA) that was reported for earlier experimental coincidence results.

Section: Resultssupporting

confidence: 58%

“…The experimental set-up used to carry out the measurements reported in this paper is essentially the same as the one used in the earlier studies (Chwirot et al 1996). Two significant modifications have been made.…”

Section: Apparatusmentioning

confidence: 99%

Electron-photon coincidence study of the collisional excitation of the Ca state

Dyl¹,

Dziczek²,

Piwiński³

et al. 1999

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“…The present work is a continuation of our previous coincidence studies of electron scattering on Ca and Cd atoms (Chwirot et al 1996, Dyl et al 1999, Piwiński et al 2002. We present the first complete coincidence data for the incident electron energies of 60 eV, 80 eV and an additional set of data for 100 eV.…”

Section: Introductionmentioning

confidence: 79%

Coincidence study of excitation of cadmium atoms by electron impact

Piwiński¹,

Dziczek²,

Kłosowski³

et al. 2006

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We present experimental values of the electron impact coherence parameters (EICP) and reduced Stokes parameters for excitation of 51P1 state of cadmium atoms. The results have been obtained using electron–photon coincidence technique for incident electron energies 80 eV and 60 eV and electron scattering angles in the range of 5° to 50°. We also present an additional set of data for electron energy 100 eV and scattering angle 50° which complements our previous results. All the experimental values are compared with theoretical relativistic distorted-wave approximation (RDWA) calculations. The first Born approximation (FBA) predictions of the alignment angle are also presented. The theoretical results are in good qualitative agreement with the experimental data.

“…Their results include the Stokes parameters and total polarization at an electron energy of 40 eV. Chwirot et al [16] presented the measured excitation parameters at an electron energy of 100 eV for six scattering angles between 10 • and 45 • . Dyl et al [17] also used an electron-photon coincidence technique but to obtain coherence parameters for electron impact excitation of the 4 1 P 1 state at 45 eV and 60 eV electron-impact energies and scattering angles between 15 • and 40 • .…”

Section: Introductionmentioning

confidence: 99%

Differential and integrated cross sections for the electron excitation of the 4¹P^ostate of calcium atom

Milisavljević¹,

Šević²,

Pejčev³

et al. 2004

Differential cross section (DCS) data for excitation of the 4 1 P o state (2.93 eV) of Ca atoms by electrons have been obtained using a crossed electron-atom beam technique. The measurements were divided into two groups. The first one consists of measurements at 10, 20, 40, 60 and 100 eV impact electron energies from 1 • to 10 • scattering angle interval. The second group of measurements are those at larger scattering angles (10 • -150 • ) at the same energies except 100 eV. Absolute values have been obtained by normalizing generalized oscillator strengths (GOS) to optical oscillator strength (OOS) in the minimum momentum transfer squared (K 2 ) limit. Integral, momentum transfer and viscosity cross sections have been determined from DCSs. A comparison is made with existing relativistic distorted wave calculation.