Anharmonic force eld, structure, and thermochemistry of CF2 and CCl2

The anharmonic force field up to quartic terms has been calculated for both CF2 and CCl2 at the CCSD(T) level of theory with large basis sets. The calculated spectroscopic parameters are in excellent agreement with the available experimental data. The equilibrium structure of CCl2 has been calculated at the CCSD(T) level of theory with the cc-pV5Z basis set ( including core correlation corrections). It is in excellent agreement with the semi-experimental equilibrium structure derived from the experimental rotational constants and the ab initio rovibrational interaction parameters. The heats of formation of CF2 and CCl2 have been calculated using the W2 method and are -193.43 and 227.96 kJ mol(-1), respectively.