Excitation phonon coupling

Using this model they have tried to look at important chemical processes at metal surfaces to deduce the role of electronic nonadiabaticity. In particular, they have tried to evaluate the importance of electron-hole-pair excitation in scattering, sticking and surface mobility of CO on a Cu(100) surface.36,37 Those studies indicated that the magnitude of energy transferred by coupling to the electron bath was significantly less than that coupled to phonons. Thus the role of electron-hole-pair excitation in... 

The elementary excitations mentioned so far are not related in any special way to the solid state and will therefore not be treated in this article. We will discuss here the following low-lying quantized excitations or quasi-particles which have been investigated by Raman spectroscopic methods phonons, polaritons, plasmons and coupled plasmon-phonon states, plasmaritons, mag-nons, and Landau levels. Finally, phase transitions were also studied by light scattering experiments however, they cannot be dealt with in this article. 

Transformation. The transformation of the Hamiltonian (2.1) which yields a weak residual excitation-phonon coupling even when the g are large has been discussed several times (4, 7, 16, 17). It prSduces a uniform shift in the excitation energy levels and a displacement in the equilibrium position of the phonons corresponding to the formation of a polaron. Since the transfer interactions J compete with this tendency to form a localized... 

Equation (4.21) can be solved by a numerical iteration scheme. This is particularly useful for excited states where no sensible guess as to A may be possible, and for interacting electron problems where no exact solutions are possible. We discuss interacting electrons and their coupling to phonons in Chapter 7. 

Pr + ( H4), and Sm + ( H5/2) ions. These studies have revealed both pure crystal-field excitations in R2CUO4 systems, as well as crystal-field excitations in RBa2Cuj06 systems that derive their Raman intensities from a strong magneto-elastic coupling with phonons. For a more detailed discussion of these studies, the reader is referred to the recent review article by Cardona (1999). 

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