In this paper the effective mass wave function of the bound shallow donor electron in Ge was used to obtain the spin-Hamiltonian. It was shown that the resonance frequency is anisotropic only if the minima of the conduction band deviate from the symmetry points (2π)/α[111], provided there is no stress. This makes it possible to determine whether the minima of the conduction band slightly deviate from the (2π)/α[111] points ornot by means of experiments of double resonance.The general expressions of the resonance frequency and anisotropic line width were obtained by taking the smoothly varying nonhomogeneous stress as perturbation. Furthermore, we calculated in detail the nonhomogeneous broadening of the resonance line under the action of the stress of dislocations in Ge generated during the growth of single crystals by the pulling method or by means of plastic deformation (edge dislocation of the [211] direction and screw dislocation of [110]). It was pointed out that the anisotropy of line width is essentially different for different types of dislocations, and also for different equivalent directions. In comparison with the experimental results of Wilson, we concluded that, as the density of dislocation is smaller than 104εcm-2, the dislocation stress is not the main cause of broadening, so that the line width should have similar anisotropy as the magnetic field is oriented in different (110) planes. When the density is larger than 105εcm-2, dislocation stress gives the main contribution to broadening. This effect can be easily examined experimentally.
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