The Development of a Quantum-Mechanical Model for the Lithium Fluoride Molecule

A quantum-mechanical model of the LiF molecule is developed using four different forms of wave functions. The most refined form (Sec. III, part iii) considers the transfer of electrons to an excited state of the F— ion and possible covalency of the bond. This leads to values of the binding energy, internuclear distance, and dipole moment which are in reasonable agreement with available data. The inclusion of about 11 percent covalent character is essential for the success of the model proposed.