A physical model is presented that aims at rationalizing the selectivity of bond breakage observed when polymethylmethacrylate is irradiated by ions in the 10–500 Kev energy range. This model, previously proposed by Brandt and Ritchie, is based on electronic collective effects. The coupling between the pure plasma oscillation at ωp and the oscillation of free electrons at (ω2k0)½ makes the whole electronic population resonant at the frequency ωrp = (ω2p+ (ω2k0))½. By computing the valence-band density of states, we are able to calculate (ω2k0) and then to deduce the theoretical value of ωrp. On the other hand, we provide an experimental measurement of ωrp and study its dependence on ion fluence by electron-energy-loss spectroscopy. The validity of the model of Brandt and Ritchie is then discussed in the light of both theoretical and experimental data.
|Original language||English (US)|
|Number of pages||16|
|Journal||Philosophical Magazine B: Physics of Condensed Matter; Statistical Mechanics, Electronic, Optical and Magnetic Properties|
|State||Published - May 1996|
ASJC Scopus subject areas
- Chemical Engineering(all)
- Physics and Astronomy(all)