The zero-field splitting and ^-values of manganocene and chromocene have been calculated. The wave functions were obtained by means of a self-consistent charge extended Hiickel method. The calculated values <7|| =2.0034 and g = 2.0033 of manganocene agree fairly well with the experimental results obtained from ESR measurements. The very large computed zero-field splitting D=-0.24 cm -1 explains that there has been observed only one ESR transition though manganocene is in a spin-5/2 state. For chromocene no ESR transition has been found until now. We therefore studied the splitting of the orbitally degenerate ground state by the combined action of spin-orbit coupling and low-symmetry perturbation. The predicted splitting is strongly dependent on the magnitude of the rhombic distortion compared to the spin-orbit interaction. The ^-values are highly anisotropic, with <7||=2.49 and <7^ = 1.97.

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In part II the magnetic resonance properties of the lowest lying excited triplet state of ferrocene has been investigated theoretically. As in the case of the ground state of chromocene (part I) we studied the splitting of the orbitally degenerate triplet state by the combined action of spin-orbit coupling and low-symmetry perturbation. The results explain the fact that no ESR spectrum has been observed in the lowest lying triplet state of ferrocene until now. There is also given an estimation of the lifetime of this state. The g-values and parameters of hyperfinestructure of the orbitally degenerate doublet ground state of cobaltocene are calculated and compared with the experimental results. The wave functions used for the calculations were obtained by a self-consistent-charge extended Hückel method.

The direct and core-polarization contributions to the Knight shift in palladium metal have been calculated taking an enhancement factor of 10 for d- and 1.28 for s-electrons. We found a large negative contribution of - 3.88% for the core electrons and a comparatively small direct contribution of 0.18% for s-electrons on the Fermi surface. Together with an estimated contribution of 0.36% for conduction electrons in s-orbitals, but not on the Fermi surface, the calculated total amount of - 3.34% is in good agreement with the experimental value of - 4% obtained by the Jaccarino plot for palladium at 0 K