A study of the charge density in ionic molecules containing F−

The structure of ionic molecules containing F− is analyzed in a model calculation of He2+F−. We study the anisotropic charge distribution and calculate multipole fields deriving from the F− polarization by the positively charged ion. The F− polarization is expected to significantly contribute to interactions between a Rydberg electron and the ionic core in other homologous systems, such as CaF, whose electronic Rydberg states were recently calculated.