Non-resonant process

Non-resonant processes include vibration-translation (V-T) processes with transfer probabilities decreasing... 

Microwave ionization of nonhydrogenic atoms, first thought to be a non-resonant process, has, by a series of experiments, been shown to be a resonant process. There is a clear parallel with optical experiments, where what had been thought to be non-resonant ionization was shown to be resonantly enhanced by Stark shifts due to the optical field [31]. As in the microwave experiments, all the... 

Note that, in contrast with the corresponding non-resonant process, there is no j8 term. Furthermore, in addition to ground state electrical properties the curly bracket expressions also contain transition dipole moments and polarizabilities. For example. 

In order to be complete, we shall now describe non-resonant processes where there is a large mismatch in energy of the oscillators. The first analogue for energy transfer was formulated by Orbach (1967). This corresponds to the situation shown as follows ... 

In a non-resonant process, the ionizing electron e is not attached to the sample molecule, but only transfers energy to it ... 

Let us concentrate first on the G peak because of the linear electronic dispersion of graphene, in principle the Raman scattering process of the G peak can be always resonant, i.e. the electronic transition can always match with real electronic states, no matter the incident excitation frequency. This is described in Fig. 4a in the case of incident resonance (scattered resonance is also possible). In general, a resonant process has a higher probability compared to a non-resonant process, so one would expect the G peak to be described only by resonant processes. However, it has been shown, both experimentally and theoretically, that quantum interference effects cancel the resonant contributions in the G peak Raman intensity. Consequently,... 

The laser combustion diagnostics techniques discussed so far utilized resonant processes, whether it be single- or multi-photon excitation, fluorescence or stimulated emission. We will now consider non-resonant processes of Raman nature. Because of its msensitivity to quenching (the lifetime of the virtual state is lO s), Raman spectroscopy is of considerable interest for quantitative measurements on combustion processes. Further, important flame species such as O2, N2 and H2 that do not exhibit IR transitions (Sect. 4.2.2) can be readily studied with the Raman technique. However, because of the inherent weakness of the Raman scattering process (Sect. 4.3) only non-luminous (non-sooting) flames can be studied. 

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