Coupling states nonadiabatic delocalization

Visual inspection of the wavefunctions reveals another feature of the nonadiabatically delocalized states, which is crucial for rationalizing the effect and building up a model. Namely, the perpendicular quantum numbers v and V3 of the weak component of these states systematically coincide with the perpendicular quanmm numbers of an adjacent adiabatically delocalized state. This suggests that weak delocalization is induced by coupling between a certain zero-order localized state and a neighboring adiabatically delocalized state... 

Figure 7. Simple two-state coupling scheme in HCN e-> CNH, according to Eq. (20). (Left) Wavefunction of the adiabatically delocalized state 241 (E = 16,612 cm ), which is assigned as (0,56,0),. This is state x ) of Eq. (20). (Right) Wavefunction of the resulting nonadiabatically delocalized state 242 (E = 16,623 cm ), which can be assigned as (2,16,0)jj( but displays the nodal structure of (0,26,0)f,j jj on the CNH side. This is state of Eq. (20). The various assignments refer to the adiabatic description (upper) and to the nodal structures in the isolated wells (lower). The value of the overlap integral Sk, is indicated along the line connecting the two states. The wavefunctions are shown in the same representation as in Eig. 6.

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