Аннотация
Abstract Electronic structure calculations of the neutral charged oxygen‐substitutional impurity in silicon are carried out within the framework of the semi‐empirical MINDO/3 method. The structure of the substitutional impurity in the silicon lattice is simulated by finite molecular cluster OSi4H12 with an equilibrium SiH bond length 0.152 nm. Account of electronic interaction for single and double excitations allows to explain the nature of the impurity displacement in silicon. The cluster choosed serves as a good model for Si‐S1 centres. The results of spin–orbit coupling calculations give information about processes determining the appearance of non‐equilibrium spin polarization in these centres. The quantitative interpretation of Si‐S1 centre ESR‐spectra angular dependence in the helium region of temperature is carried out on the basis of the solution of the equation of motion for a triplet density operator. The dependence of the stationary concentration of triplet centres on magnetic field and crystal orientation is obtained.