Thallium halides have CsCl structure except TlF which has an orthorhombically distorted variant NaCl–type structure. At the normal room temperature it has a distorted rock salt structure. The nature and the physical properties of the thallous halides have attracted an increased interest in the study of their lattice dynamics .The dynamical behavior of thallium fluoride (TlF) have been studied by using van der Waals three-body force shell model (VTBFSM), which incorporates the effects of the van der Waals interaction with long-range Coulomb interactions, three-body interactions and short-range second neighbour interactions in the framework of rigid shell model (RSM).In present paper the variations of Debye temperature with absolute temperature have been theoretically calculated for thallium fluoride using (VTBFSM).
