THE RYDBERG SPECTRUM OF CAF AND BAF - CALCULATION BY R-MATRIX AND GENERALIZED QUANTUM-DEFECT THEORY

R-matrix theory combined with generalized quantum defect theory is use d to calculate the electronic spectrum of the CaF and BaF molecules fr om the ground state up near the ionization limit. The approach, an eff ective one-electron method similar in spirit to the ligand-field model of Rice, Martin. and Field [S. F. Rice, H. Martin, and R. W. Field, J . Chem. Phys. 82, 5023 (1985)] and to the electrostatic polarization m odel of Torring, Ernst. and Kandler [T. Torring, W. E. Ernst, J. Kandl er, J. Chem. Phys. 90, 4927 (1989)] removes many of the limitations in herent in the previous work. The resulting level energies (effective p rincipal quantum numbers) are in good agreement with the available exp erimental data and constitute the first quantitative theoretical calcu lation of the full electronic spectrum of CaF and BaF. Limitations and possible extensions of the theory are discussed, and quantum defects of high orbital angular momentum states are predicted. (C) 1997 Americ an Institute of Physics.