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    Direct measurement of P+ for electron impact excitation of H(2p) at 54.4 eV


    Gradziel, Marcin and O'Neill, R.W. (2004) Direct measurement of P+ for electron impact excitation of H(2p) at 54.4 eV. Journal of Physics B: Atomic, Molecular and Optical Physics, 37 (9). pp. 1893-1907. ISSN 0953-4075

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    Abstract

    We report results of direct measurements of the reduced Stokes parameters \skew{-1}\bar{P_1}, \bar{P_2} and \skew{-1}\bar{P_3} for electron impact excitation of H(2p) at 54.4 eV over the scattering range 10–40°. These three parameters have been measured simultaneously for the first time using a VUV double-rotation polarization analyser consisting of a MgF2 retarder followed by a SiO2 reflection linear polarizer. As expected, our measurements for \skew{-1}\bar{P_1} and \bar{P_2} are in good agreement with theoretical calculations and previous experimental data. Our data for \skew{-1}\bar{P_3} differ significantly from previous experimental measurements and theoretical calculations. Consequently, we find that the coherence parameter P+ deviates significantly from unity at 30°. If correct, this signifies that spin-exchange scattering may be more important than has previously been thought.

    Item Type: Article
    Additional Information: This work was supported by an Enterprise Ireland Basic Research Grant. M L Gradziel gratefully acknowledges the receipt of a Daniel O’Connell Research Scholarship from NUI Maynooth. The work would not have been possible without the excellent technical support of David Watson and Bill Lanigan.
    Keywords: Direct measurement; electron impact excitation; reduced Stokes parameters;
    Academic Unit: Faculty of Science and Engineering > Experimental Physics
    Item ID: 9790
    Identification Number: https://doi.org/10.1088/0953-4075/37/9/010
    Depositing User: Dr. Marcin Lukasz Gradziel
    Date Deposited: 17 Aug 2018 14:02
    Journal or Publication Title: Journal of Physics B: Atomic, Molecular and Optical Physics
    Publisher: IOP Publishing
    Refereed: Yes
    Funders: Enterprise Ireland (EI)
    URI:

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