Polarisation of the OH(A 2Σ+, v′ = 0 → X 2Πi, v″ = 0) fluorescence produced electron impact on water vapour

K. Becker, B. Stumpf, G. Schulz

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We measured the OH(A 2Σ+ → X 2Πi) fluorescence polarisation in the vibrational 0—0 band system after dissociative excitation of water by electron impact for energies from 11.9 eV up to 500 eV using a setup of crossed electron and H2O beams. The measured polarisations as a function of the electron energy take a course from being mainly unpolarised in the high energy region to negative polarisation values when the energy of the impinging electrons approaches threshold. Quantitatively we find −5.2 ± 1.1% at 11.9 eV. A tentative explanation of our results is made and it appears that the measurement of the OH fluorescence polarisation being equivalent to an anisotropic angular distribution of the emitted photons is a sensitive probe of studying the electron impact induced dissociation mechanism of the water molecule.

Original languageEnglish (US)
Pages (from-to)31-38
Number of pages8
JournalChemical Physics
Issue number1-2
StatePublished - 1980

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry


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