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Absolute photoabsorption and photoionization studies of the hydrogen halides HC1, HBr, and HI, by dipole (e,e) and (e,e+ion) spectroscopies in the UV,VUV and soft x-rays regions

University of British Columbia

The absolute differential oscillator strengths (cross sections) for the photoabsorption spectra of the three hydrogen halide molecules HC1 (5-280 eV), HBr (5-300 eV), and HI (5-120 eV) have been obtained by using dipole (e,e) spectroscopy, at both low (1 eV fwhm) and high (0.05-0.1 eV fwhm) resolution. Data for the valence and selected inner shells (CI 2p, Br 3d, and I 4d) have been obtained at equivalent photon energies from the UV to soft X-ray regions. The absolute oscillator strength scales were determined by use of the VTRK (S(0)) sum rule for HC1, and the dipole polarizability (S(-2)) sum rule for HBr and HI. The value of the dipole polarizability derived from the VTRK normalized spectrum of HC1 is in very good agreement with published experimental values. In further experiments, dipole (e,e+ion) spectroscopy has been used to investigate the molecular and dissociative photoionization of HC1 and HBr, in the valence and selected inner shell (CI 2p, Br 3d) regions. Photoion branching ratios for molecular and dissociative photoionization determined from time-of-flight mass spectra have been used together with the absolute photoabsorption data to obtain partial photoionization differential oscillator strengths. Photoionization efficiencies have also been obtained. A consideration of the partial differential oscillator strengths for molecular and dissociative photoionization together with the electronic state partial differential oscillator strengths (obtained from earlier dipole (e,2e) studies, Chem. Phys. 83 (1984) 391, Chem. Phys. 98 (1985) 367) provides information concerning the dipole-induced breakdown pathways of HC1 and HBr.

Thesis/Dissertation

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2009-03-12

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http://hdl.handle.net/2429/5937

Chemistry

University of British Columbia

UBCV

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