EN
In this paper we introduce a new model describing the coupling of ^{2}E and ^{4}T_{2} states of octahedrally coordinated Cr^{3+} ion, which includes spin-orbit and electron-lattice interactions and takes into account the electronic structure of both states. The model is used to calculate doublet lifetime. We have applied this model to the series of Cr^{3+} doped garnets characterized by the varying crystal field parameter 10 Dq and O_{h} symmetry of the Cr site and to the kyanite (Al_{2}O_{3}:SiO_{2}), which is the case of different Cr^{3+} sites in one material, characterized by the relatively large component of the low symmetry crystal field. The agreement with experiment is reasonable.