B3LYP calculations of density functional theory （DFT）with 6-311+G（3df,2p）basis set level are used to investigate the equilibrium structures and intramolecular rearrangement reactions of the linear BrSSH and branched S=SBrH isomers.The calculated results shows that the linear structure is more stable than the branched structure (lower 73.1kJ·mol-1 corrected with zero point vibrational energy) energetically.The calculated energy barriers for the intramolecular bromine atom transfer and hydrogen atom transfer isomerization processes are 174.1kJ·mol-1 and 173.7kJ·mol-1,respectively.The kinetic results demonstrate that the isomerization is a unimolecular one,and the reaction rate is rather slow.It is consistent with thermodynomical results.So the isomerization process should proceed via the other likely processes.
