Absolute cross section measurements for the scattering of low- and intermediate-energy electrons from PF₃. II. Inelastic scattering of vibrational and electronic excitations

Abstract

As a sequel paper to our study of the elastic scattering for electron collisions with phosphorus trifluoride, PF₃ molecules, we report absolute inelastic differential and integral cross sections (DCS and ICS) of vibrational excitations for the compound fundamental vibrational modes v₁₃ (v₁ + v₃), v₂₄ (v₂ + v₄), and their sum in the impact energy range of 2.0-10 eV and over a scattering angle range of 20⁰ -130⁰. The measured angular distributions of scattered electron intensities for the present inelastic scattering are normalized to the elastic peak intensity corresponding to the DCSs of He. These vibrational excitation measurements demonstrate the presence of resonances around 2 eV and also around 6-10 eV. In addition, a generalized oscillator strength analysis is applied to derive oscillator strength f₀-values and (unscaled Born) ICSs from the corresponding DCSs measured for the low-lying optically allowed 8a₁ → 7e (σ*)excitation band, which is assigned as the Jahn-Teller splitting and 8a₁⁻¹→ 4s Rydberg transition at impact energies of 100, 200, and 300 eV, over a scattering angle range of 1.0⁰ -15⁰. The f₀-values obtained in the present study are compared with the results of previous photoabsorption and pseudo-optical measurements. The unscaled Born ICSs are compared with the binary-encounter f-scaled Born ICSs estimated over a wide impact energy region from the excitation thresholds.