AN ASYMPTOTIC-POTENTIAL METHOD FOR HIGH-L RYDBERG LEVELS OF CALCIUM

The long-range asymptotic form of the polarization potential for an el ectron interacting with a Ca+ 'core' is evaluated up to terms of order r(-8). The static dipole polarizability of Ca+ is calculated to be 73 .8 au, while higher-order polarizabilities are found to be very much l arger. Energies of 4snl Rydberg levels for l = 3, 4 and 5 are evaluate d in first- and second-order perturbation theory and it is suggested t hat 4s5g (1)G is located at 44 874.55 +/- 0.2 cm(-1). Frequencies for 4snf 1F(o) - 4sng (1)G (n = 23-25) microwave transitions are compared with experiment and with a model-potential calculation which corrects for core-penetration effects.