A theoretical study of the kinetics of the forward and reverse reactions HIÂ +Â CH3Â =Â IÂ +Â CH4

► Thermodynamic and kinetic parameters are calculated using ab initio molecular orbital methods. ► Calculated reaction enthalpy at 0 K is in excellent agreement with its experimental counterpart. ► Rate constants are calculated from 250 to 2500 K and compared to the available literature data.