AB-INITIO CALCULATION OF THE NMR SHIELDING AND INDIRECT SPIN-SPIN COUPLING-CONSTANTS OF FLUOROETHYLENE

The spin-Hamiltonian parameters that characterize the high-resolution NMR spectrum of C2H3F (i.e., the full set of six nuclear shielding con stants and 15 indirect nuclear spin-spin coupling constants) have been calculated using multiconfigurational self-consistent field (MCSCF) w avefunctions. The dependence of the parameters on the basis set and on the correlation treatment is investigated. Although convergence is di fficult to achieve, for most parameters a systematic improvement is fo und with extension of the atomic orbital basis and the MCSCF configura tion space. All the final results are in satisfactory agreement with a vailable experimental data.