Molecular Orbital Investigation of CF and SiF and Their Positive and Negative Ions

Abstract

Accurate Hartree–Fock self-consistent-field wavefunctions have been computed for CF, CF+, and CF− at several internuclear separations by the Roothaan expansion method. Similar wavefunctions were also computed for SiF, SiF+, and SiF− at the parent molecule internuclear separation. A Dunham analysis of the energy curves for the three CF species yielded values for the spectroscopic constants. Other properties deduced in the present research include the first and second ionization potentials, electron affinities, and dipole and quadrupole moments for CF and SiF. The dipole moment calculated for CF is consistent with a charge distribution corresponding to a C−–F+ configuration. In addition, the correlation energies of a number of light-element diatomic fluorides have been deduced from literature data and from results given in the present paper. It appears that the correlation energy increment between adjacent diatomic fluorides is virtually constant for molecules of the first row of the periodic table.