ABSOLUTE OSCILLATOR-STRENGTHS FOR THE PHOTOABSORPTION OF SILANE IN THE VALENCE AND SI 2P AND 2S REGIONS (7.5-350 EV)

Absolute photoabsorption oscillator strengths (cross sections) for the valence and Si 2p discrete regions of silane have been measured using high resolution (similar to 0.05-0.1 eV fwhm) dipole (e, e) spectroscopy. Long range (7.5-350 eV) lower resolution data (1 eV fwhm) have also been obtained, from which the absolute oscillator strength scale has been determined using TRK (i.e. S(0)) sum-rule normalization. The accuracy of the presently reported measurements has been tested using the S(-2) sum-rule: Evaluation of the S(-2) sum using the presently reported data gives a dipole polarizability for silane within 0.2% of the experimental value. The present valence shell measurements were undertaken in order to investigate the differences between earlier low resolution dipole (e, e) work (Cooper et al., Chem. Phys. 140 (1990) 133) and subsequent valence shell synchrotron radiation photoabsorption measurements reported by Kameta et al. (J. Chem. Phys. 95 (1991) 1456). The presently reported high and low resolution absolute photoabsorption oscillator strengths are much more consistent with the direct photoabsorption measurements than the earlier dipole (e, e) work(within similar to 15%). The resolution of the present high resolution data is sufficient to allow absolute photoabsorption oscillator strengths to be determined for many of the individual electronic transitions in the Si 2p discrete spectrum.