Crossing resonance energy

Table 8.2. Threshold energy, cross section maximum, resonance energy, and FWHM for different photo-induced reactions...

Very large rate constants have been found for near resonant energy transfer between infrared active vibrations in CO2 Such near-resonant transitions and their dependence on temperature have also been studied for collisions between vibrationally excited CO2 and other polyatomic molecules as CH4, C2H4, SF et al. The deactivation cross-sections range from 0.28 for CH3F to 4.3 for SFs at room temperature, and decrease with increasing temperature. 

Table 3 Rate Constant k, Resonance Energy E Resonance Width Electron Density and Cross Section Ch (From Refs. 10 and 11.)...

Fig. 14.1 Two atoms, A and B have energy levels as shown. Initially atom A is in its excited state, and atom B is in its ground state. If the energy of the excited state of atom B could be tuned by some means, we would expect the cross section for resonant energy transfer from atom A to atom B to increase at resonance as shown on the right (from ref. 5).

Figure 5. The cr-energy curve (a) and the -avoided crossing VB diagram (b) in conjugated //-electron—//-center species. Note that in the narrow range of the permitted distortion, d di, the vertical resonance energy is...

One expects to observe a barrier resonance associated with each vibra-tionally adiabatic barrier for a given chemical reaction. Since the adiabatic theory of reactions is closely related to the rate of reaction, it is perhaps not surprising that Truhlar and coworkers [44, 55] have demonstrated that the cumulative reaction probability, NR(E), shows the influence barrier resonances. Specifically, dNR/dE shows peaks at each resonance energy and Nr(E) itself shows a staircase structure with a unit step at each QBS energy. It is a more unexpected result that the properties of the QBS seem to also imprint on other reaction observables such as the state-to-state cross sections [1,56] and even can even influence the helicity states of the products [57-59]. This more general influence of the QBS on scattering observables makes possible the direct verification of the existence of barrier-states based on molecular beam experiments. 

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