Abstract:
Ab initio SCF studies were performed with Cu and F basis sets of near-Hartree-Fock (HF) limit quality to obtain accurate SCF results for the molecular ground state properties of CuF, CuF, CuF, CuF, and CuF , as well as for the first two low-lying excited states of CuF. A study on the effects of electron correlation was carried out by Møller-Plesset (MP) and configuration interaction (Cl) calculations. The effect of relativity on theCu nuclear quadrupole coupling in CuF was determined by use of a coupled HF procedure for a first-order spin-orbital-averaged Pauli operator. At the HF level theCu coupling constant was found to be 35.8 MHz (in eqQ h), while allowing for relativity the value was reduced to 29.1 MHz, which is in better agreement with the experimental value of 22.0 MHz. The calculated molecular properties for CuF [r = 1.737 Å, D=4.38 eV, ω = 562 cm (MP4);r= 1.796 Å, D = 3.91 eV, ω=585 cm (CISD)] were in good agreement with experiment (r = 1.745 Å, D = 4.43 eV, ω=623 cm). The adiabatic ground-state potential curve of CuF avoids crossing near the equilibrium distance between the two ionic potential curves Cu-F and Cu-F. At the crossing point the Cu and F electric field gradients show a sharp discontinuity.