For the first time we report on temperature dependence of Davydov splitting value FTIR spectra study for the in-phase CH(2) rocking vibrations of methylene chains in crystalline cholesteryl myristate (CholC(14)) for the temperature region from 100 K to the isotropic liquid transition point. A statistic dynamic model in terms of stochastic equations is used to explain the obtained results by accounting the damping of vibrational excitons on positional defects. Genesis of such defects is related with. transition in different liquid crystal phases (smectic phase and cholesteric phase for cholesteryl myristate). Good agreement between the experimental data and the results of such dependence computer fitting is observed.