Investigation of Thermodynamic Properties of Halomethanes Using High-Level Ab Initio Computations: Evaluation of Enthalpy of Formation and Carbon-Halogen Bond Dissociation Energies

Thermodynamic properties of halomethanes compounds were investigated using high-level ab initio computations. HF, MP2 and B3LYP at different basis sets and composite methods CBS-QB3, G3MP2 and G4 were computed for their ability to predict enthalpy of formations and carbon-halogen bond dissociation energies of halomethanes containing F, Cl or Br. G3MP2 and G4 have shown an excellent agreement with the available experimental data. The results were compared with benchmark G4 values. Moreover, bond dissociation enthalpies (EBD) were computed using direct method and isogyric method. The two methods gave similar linear square fit R2 related to G4 method.