Anomalous vibrational excitation in the small angle scattering of He+ from HCl at Elab=20-60 eV
Energy loss spectra of forward scattered He+ ions in collisions with HCl are reported for collision energies (E(lab)) in the range 20-60 eV. The spectra extend up to total energy transfers of about 2.5 eV, where the intensity is 6 orders of magnitude less than the elastic forward peak. At large ener...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
American Chemical Society, USA
1995
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| Subjects: | |
| Online Access: | http://irep.iium.edu.my/35864/ http://irep.iium.edu.my/35864/ http://irep.iium.edu.my/35864/ http://irep.iium.edu.my/35864/1/JPC1995.pdf |
| Summary: | Energy loss spectra of forward scattered He+ ions in collisions with HCl are reported for collision energies (E(lab)) in the range 20-60 eV. The spectra extend up to total energy transfers of about 2.5 eV, where the intensity is 6 orders of magnitude less than the elastic forward peak. At large energy transfers a number of broad maxima indicating a propensity for large Delta v transitions are observed. Three-dimensional quasiclassical trajectory calculations treating HCl as a rigid rotor for the long range ion-dipole/quadrupole He+-HCl interaction and a short range repulsion corresponding to the isoelectronic He+-Ar account for much of the energy transfer at low Delta E. At higher Delta E, the rigid rotor model is dearly inadequate and a better description of the experiment requires consideration of high lying repulsive states of HCl+ which appear to be temporarily accessed by charge transfer. |
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