Transition metal dichalcogenides (TMDCs) exhibit layered structures, similar to graphene, and hence are very attracting materials in science and technology. Among this materials, MoS 2 is investigated in the bulk, monolayer and nanocluster forms. In the present work, we study small (MoS 2 ) n (n=1-10) nano-clusters. First, evolutionary algorithm along with the full-potential density functional theory (DFT) computations are employed to perform a comprehensive search for the stable structures of stoichiometric (MoS 2 ) n nano-clusters (n = 1 - 10), within three different exchange-correlation functionals. After finding the most stable structures of the clusters, their various properties including binding energy, second-order energy difference and HOMO-LUMO gaps are investigated. The electronic properties and energy gap of the lowest energy isomers were computed within several scheme , including semilocal PBE and BLYP functionals, hybrid B3LYP functional, SCF and many body based DFT+GW approach. I n the following, The vibrational properties and IR spectra of the energetically most stable structures are also addressed and the calculated vibrational free energy is used to investigate finite temperature effects for T=0-1000K on the abundant of the clusters..
