Coupling strength parameter

In order to obtain a formula for the energy difference between the complete ground state energy E and the noninteracting energy Eks, and thus for E c, the interaction Hamiltonian H = H- is supplemented by a dimensionless coupling strength parameter g in such a way,... 

Both the cluster and the periodic calculations indicate a similarity to the Newns-Anderson model for metal adsorbates, in that both energy shifts, and broadenings need to be included in models of electron transfer, as shown schematically in Fig. 13. It will be a challenge in the near future to incorporate the increasingly accurate calculations of the crucial electronic coupling-strength parameter in existing dynamical models of the surface electron transfer processes. 

Fig. 9.1. Left-hand side Representation of an elastic potential energy surface. It has the general form (6.35) with coupling strength parameter e = 0. In case (a), the equilibrium bond distance in the electronic ground state equals the equilibrium separation of the free BC fragment. The heavy arrows schematically indicate two representative trajectories starting at the respective FC points. Right-hand side The corresponding final state distributions.

Fig. 8.13. Calculations for perturbations by an antiresonance for (a) positive and (b) negative values of the coupling strength parameter near a leading member of the series, showing the vanishing width for positive values of coupling. The dashed curve shows the spectrum in absence of coupling, which is the profile of the antiresonance (after J.-P. Connerade [376]).

Mies and Krauss " derived analytical expressions for the decay rates from a set of resonance scattering states i with density q coupled with equal coupling strength (parameter r, ) to a continuum corresponding to channel a). Their result can be written in the form of equation (55) ... 

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