| Themes > Science > Physics > Molecular Physics > Excitation Energy Transfer and Energy Migration > Theoretical Methods and Advances > Electron-Impact Excitation |
For atoms, an extensive database of electron-impact excitation cross sections exists. However, due to their corrosive and reactive nature, some atoms relevant to plasma processing (e.g. F, Cl, Br) have not been studied. In principle, there is no reason that these atoms could not be studied. Vibrational excitation data are available for many molecules, but only a few that are used in plasma processing, again due to the corrosive nature of many plasma processing molecules. Exceptions are CF4, SF6, and some freons. There is also a shortage of measured data for electronic excitation (particularly to stable states) of complex molecules. Theoretical methods for calculating the electronic excitation of molecules are maturing and, when properly benchmarked by measurements, can provide cross sections with adequate accuracy. |
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