AN MRD-CI STUDY OF LOW-LYING ELECTRONIC STATES IN CAF

Dipole moments and various spectroscopic constants of some low-lying electronic states of the CaF molecule have been calculated using the multireference single- and double-excitation configuration-interaction (MRD-CI) method. The electronic structure of the highly ionic molecule in various excited states can be explained in terms of different polarisations of the mainly Ca-centered valence electron in the field of the F- anion. Plots of natural orbitals occupied by the valence electron in the different states give a qualitative picture of the charge distribution and provide a visualisation of the different polarisations of the valence electron in the various states. Comparisons with the electrostatic polarisation model of Torring, Ernst and Kandler (TEK model) are made. The unknown A' 2-DELTA-state is predicted to lie about 21200 cm-1 above the ground state.