As stressed in Introduction of Part I, it is the important problem in the theory of semiconductor to work out theoretically the so-called quasi-atomic states lying between the energy bands of the body crystal, which states may be considered to behave partly in an atomic way and partly in a crystal lattice one. For the paramagnetic crystal of the complex salts of rare earth elements the electronic system within the incompleted shell of the mentioned atoms has been dealt with approximately in an atomic way in which the system can be reduced to an isolated one under the influence of the electrostatic field of crystal symmetry due to the surrounding ions, taking into account of the screening effect of the outer electrons belonging to the rare earth atoms. Such a method of approximation can not be applied generally to the quasi-atomic states in semiconductors owing to the strong coupling with the ions in crystal. As shown in the comparison with the experimental observations, Tibbs' theory for the F-centers seems to be unsatisfactory mainl due to the disregard of the atomic structure in the neighbourhood of negative ion vecancy. Actually his wave functions of trapped electron in F-center are shown to extend over the region involving several atomic ions, which fact leads us to suggest the group binding of electron due to neighbouring ions in the crystal. In order to improve Tibbs' theory from the viewpoint discussed above, we shall here propose a new method of approximation to the quasi-atomic states in the crystal in a close connection with the electronic structure of F-center in coloured alkali halide crystals.