Molecular, thermodynamic, and kinetic parameters of the free radical C2H5 in the gas phase

The wave function, energy, equilibrium geometry, and normal vibration frequencies of the ground state of the free radical CA were obtained by ab initio calculations with inclusion of electron correlation effects at the UB3LYP/6-311++G** level. The resulting molecular parameters were used to estimate the thermodynamic functions of an ideal gas of C2H5.. From the thermodynamic functions of C2H5., I-., C2H5I, C2H4, and HI and the kinetic curves of isothermal pyrolysis of ethyl iodide, the absolute rate constants of elementary reactions of free ethyl radical and the mentioned iodine compounds were estimated. The dissociation energy E-D,E-0(C2H5-I) and the standard formation enthalpy Delta(f)H(298)(0) (C2E5.) were found.