Radiative transitions and van der Waals coefficients for francium

Francium has been the least-studied alkali-metal atom until recently. We pr esent accurate calculations for the discrete and continuum optical transiti ons, and dispersion coefficients for two colliding francium atoms. Spinorbi t coupling is explicitly included and the influence of core polarization on the energies and the electric dipole operator is considered. Predictions f or a range of transition amplitudes that are needed for parity violation ex periments are made. The van der Waals coefficients for the long-range colli sion of two-groundstate Fr atoms in different fine-structure levels show a departure from an established trend in other alkali-metal atoms. We comment on the differences. [S1050-2947(98)50312-5].