J. Horáček

On shooting methods for calculation of potential resonances

Two shooting methods for calculation of potential (shape) resonances are described and their efficiency tested. It is found that although both methods are based on calculation of the Siegert (i.e. exponentially increasing non-normalizable) state, the methods are stable and very accurate values of resonance energies and widths are obtainable. It is hoped that the resonance parameters obtained here can serve as test examples for various approximate methods for calculating resonance energies and widths.

Dissociative electron attachment to HBr: A temperature effect

The effects of rovibrational temperature on dissociative electron attachment to hydrogen bromide has been investigated from the experimental and theoretical point of view. Theoretical calculations based on the nonlocal resonance model predict a strong temperature effect on the Br{sup -} fragment ion yield due to population of higher vibrational and rotational states. A crossed beam experimental setup consisting of a temperature controlled effusive molecular beam and a trochoidal electron monochromator has been used to confirm this prediction. The high degree of agreement between experiment and theory indicates the validity of the theoretical model and its underlying physical picture.

Improved nonlocal resonance model for electron – HCl collisions

We present an improved nonlocal resonance model for electron-HCl collisions. The short-range part of nthe model is based on ab-initio electron scattering eigenphase sums calculated using the Schwinger Multichannel nmethod and the long-range part on the potential curve of the bound HCli anion. We have calculated cross sections nfor vibrational excitation and dissociative electron attachment. For all collision processes where quantitative nexperimental data are available, the new model agrees with experiments better than the previous model.

Resonances in low-energy rare-gas atom scattering

Precise values of energies and widths of low-lying resonances in some rare-gas atom systems (Ar-Ar, Ne-Kr, Ne-Xe) are reported.