Faculté des sciences

Electron scattering in Pt(PF₃)₄: Elastic scattering, vibrational, and electronic excitation

Allan, Michael

In: Journal of Chemical Physics, 2011, vol. 134, no. 20, p. 204309

Experimental absolute differential cross sections for elastic scattering, and for vibrational and electronic excitation of Pt(PF₃)₄ by low-energy electrons are presented. The elastic cross sections have a deep angle-dependent Ramsauer-Townsend minimum (Emin = 0.26 eV at θ = 135°). The angular distributions of the elastic cross section at and above 6.5 eV show an... Plus

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    Summary
    Experimental absolute differential cross sections for elastic scattering, and for vibrational and electronic excitation of Pt(PF₃)₄ by low-energy electrons are presented. The elastic cross sections have a deep angle-dependent Ramsauer-Townsend minimum (Emin = 0.26 eV at θ = 135°). The angular distributions of the elastic cross section at and above 6.5 eV show an unusually narrow peak at an angle which decreases with increasing energy (it is at 40° at 20 eV). Wavy structure is observed at higher angles at 15 and 20 eV. Vibrational excitation cross sections reveal five shape resonances, at 0.84, 1.75, 3.3, 6.6, and 8.5 eV. The angular distributions of the vibrational cross sections have a strong forward peak and are nearly isotropic above about 60°. Electronically excited states are characterized by electron energy-loss spectra. They show a number of unstructured bands, the lowest at 5.8 eV. They are assigned to Rydberg states converging to the 1st and 2nd ionization energies. The cross sections for electronic excitation have very high forward peaks, reaching the value of 50 Ų at 50 eV and 0° scattering angle. Purity of the sample was monitored by the very low frequency (26 meV) Pt−P stretch vibration in the energy-loss spectra.