ANALYSIS OF SPECTROSCOPIC DATA IN KONDO SYSTEMS

The dynamics of the impurity spin in the Kondo problem has been studie d in detail in the context of specific spectroscopic tools. The bosoni zed form of the Kondo Hamiltonian has been used to derive complete lin e-shape expressions relevant for interpreting NMR, Mossbauer, and ESR experiments. The calculation is equivalent to the so-called dilute-bou nce-gas approximation in the treatment of the recently introduced spin -boson Hamiltonian. Analytical results are derived for longitudinal an d transverse relaxation rates, NMR Knight shift, and the ESR g shift. From these, several known perturbative results, including the Abrikoso v law, are recovered as special cases. The more general results derive d here have been used to analyze a wide variety of spectroscopic data and the fits are found to be very satisfactory.