Resonant Excitation Process Research Articles

Resonant Vibrational Excitation of O2 by Slow Electron Impact

Fano's theory on configuration mixing for many channel case has been applied to investigate the resonant vibrational excitation process of an oxygen molecule by low energy (less than 1 eV) electron impact. It has been shown that each channel width is proportional to the 5th power of the wave number of an incident or ejected electron. The energy integrated cross section for resonant vibrational 0→1 excitation via an intermediate vibrationally excited oxygen molecular ion state O 2 -* (υ'=6) is estimated to be 6.4×10 -3 a 0 2 eV. This is in fairly good agreement with the experimental results by Linder and Schmidt (Z. Naturforsch. 26a (1971) 1617): 9.0×10 -3 a 0 2 eV, and by Spence and Schulz (Phys. Rev. A 2 (1970) 1802): 1.4×10 -3 a 0 2 eV. It has been shown that the characteristic feature of branching ratio can also be explained by the k 5 rule.

Vibrational Excitation in CO by Electron Impact in the Energy Range 10-90 eV

The ratio of the scattering intensity for the ${v}^{\ensuremath{'}\ensuremath{'}}=1$ excitation to the elastic scattering intensity at 40\ifmmode^\circ\else\textdegree\fi{} and 80\ifmmode^\circ\else\textdegree\fi{} scattering angles has been determined for 10-90-eV impact energies for electron scattering by CO. These ratio curves exhibit broad peaks near 20-eV impact energy which cannot be accounted for by plane-wave calculations based on potential scattering models. The peaks are indicative of a resonant excitation process (or processes) in the ${v}^{\ensuremath{'}\ensuremath{'}}=1$ channel in the range 15-25 eV.

Angular dependence of collision-induced excitation of H 2+ ions

We have measured the angular dependence of the dissociation cross section of H 2 + ions incident at 3–10 keV on rare gases and H 2. The results show qualitative agreement with theoretical predictions and also that for small internuclear distances in the H 2 + molecule the dissociation proceeds primarily from the 2pσ u state. For these internuclear distances the largest departure from the predicted curves has been interpreted as a simultaneous excitation of projectile and target atom. We have also measured the relative dissociation cross section as a function of the H 2 + internuclear distance. These measurements reveal evidence for a resonance excitation process.