Electric properties of ionic diatoms: LiF

Abstract

The dipole and quadrupole moments and polarizabilities of the LiF molecule have been calculated using many-body perturbation theory (MBPT) and a large and flexible polarized basis set of Gaussian functions. The fourth-order MBPT results, obtained at the experimental bond distance, R e=2.9553 au, are as follows: dipole moment μ z =2.4592 au, quadrupole moment Θ zz =4.520 au, dipole polarizability α xx =10.57 au, α zz =10.46 au, quadrupole polarizability C xx,xx =18.93 au, C zz,zz =21.32 au, C xz,xz =15.80 au. The calculated dipole moment is in excellent agreement with the known experimental value (2.453 au). The present high-level correlated values of the electric properties of LiF are discussed in terms of their implication for electrostatic interaction models of ionic diatoms and ionic crystals.