Time dependent self consistent field properties

To make the discussion more quantitative, let us now consider the doping dependence of Rh(S,T) in terms of the f-f -/model using the saddle-point and relaxation time approximations, where FS and correlation effects are involved via the renormalized SB band (Eq. 33). As we have pointed out above, in our approach the SB quasi-particle band dispersion has to be determined in a self-consistent way at each doping level 5. This should be in contrast to the NZA SB mean-field approach to the t-f -/model of Chi and Nagi [61] where, in the 7 -> 0 limit, the calculation of transport properties is based on the simple replacement Sj — Sj = -2 (5[(cos x + cos ) + 2(r7r)cos cosAy] ofthe non-interacting band dispersion (Eq. 2). 

A particularly convenient improved approximation to this end can be obtained by use of self-consistent, first order, time-dependent perturbation theory. The essential physics to be included is that the external field distorts the atomic charge cloud (by admixture of excited orbitals) which in turn creates an electrostatic potential acting on the system, The self-consistent response of the electrons produces a mean field which reflects the atomic dielectric properties and alters the photoionization amplitudes. If this linear response approach is applied to the HFA one obtains precisely the RPAE, In what follows we consider the same approximation applied to the LDA. Given this parallelism, emphasis will be placed on direct comparisons with the RPAE,... 

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