Adiabatic potential energy surfaces, crossing

Figure 21. Family of reactive trajectories in the ground adiabatic potential energy surface determined by Eq. (13). Crosses indicate the caustics. Taken from Ref. [29].

Not shown to the quasi-diabatic potential energy surfaces in Fig. (3) there is a adiabatic potential energy surface. This is distinguished by the maximum at the crossing point nil. The system has a saddle-point structure. In the regions about the cis and trans attractors there is no difference between them. Between 2%1 i... 

We refer to Chapter 4 for a detailed discussion on the definition and explicit construction of diabatic states. The diabatic representation is generally advantageous for the computational treatment of the nuclear dynamics if the adiabatic potential-energy surfaces exhibit degeneracies such as conical intersections. Moreover, the diabatic representation often reflects more clearly than the Born ppenheimer adiabatic representation the essential physics of curve crossing problems and is thus very useful for the construction of appropriate model Hamiltonians for polyatomic systems. 

The adiabatic potential energy surface below the intersection point possesses three equivalent minimum regions. One of these surface minima is seen in the cross section in Figure 3 and is labeled as point Min. The three minima on the surface are separated by three saddle-point transition states. Point TS in the Figure 3 cross section is the transition state between the two other... 

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