MREI-model calculations of optical phonons in layered mixed crystals of 2H-polytype of the series SnS2−xSex (0⩽x⩽2)

Optical phonon frequencies have been calculated for 2H-polytype of layered mixed crystals in the series SnS2−xSex (0⩽x⩽2), using MREI-model. The model was modified to make it applicable in this type of series. Various force constants and the values of local and gap modes have been reported. The model successfully confirms the two-mode behavior exhibited by the series and the calculated values agree very well with experimentally observed values, reported earlier.