Removal energies and hyperfine constants of the lowest four ns, np 1/2 and np 3/2 states in Na, K, Rb and Cs are calculated; removal energies of the n=7-10 states and hyperfine constants of the n=7 and 8 states in Fr are also calculated. The calculations are based on the relativistic single-double (SD) approximation in which single and double excitations of Dirac-Hartree-Fock (DHF) wave functions are included to all-orders in perturbation theory. Using SD wave functions, accurate values of removal energies, electric-dipole matrix elements and static polarizabilities are obtained, however, SD wave functions give poor values of magnetic-dipole hyperfine constants for heavy atoms. To obtain accurate values of hyperfine constants for heavy atoms, we include triple excitations partially in the wave functions. The present calculations provide the basis for reevaluating PNC amplitudes in Cs and Fr.

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The use of basis sets formed from B-splines in non-relativistic and relativistic atomic calculations is described.

Excitation energies for 2lϪ3lЈ hole-particle states of Ne-like ions are determined to second order in relativistic many-body perturbation theory ͑MBPT͒. Reduced matrix elements, line strengths, and transition rates are calculated for electric-dipole (E1), magnetic-quadrupole (E2), magnetic-dipole (M 1), and magneticquadrupole (M 2) transitions in Ne-like ions with nuclear charges ranging from Zϭ11 to 100. The calculations start from a 1s 2 2s 2 2p 6 closed-shell Dirac-Fock potential and include second-order Coulomb and BreitCoulomb interactions. First-order many-body perturbation theory ͑MBPT͒ is used to obtain intermediatecoupling coefficients, and second-order MBPT is used to determine the matrix elements. Contributions from negative-energy states are included in the second-order E1, M 1, E2, and M 2 matrix elements. The resulting transition energies are compared with experimental values and with results from other recent calculations. Trends of E1, E2, M 1, and M 2 transition rates as functions of nuclear charge Z are shown graphically for all transitions to the ground state.

The relativistic random-phase approximation (RRPA) is applied to study radiative transitions from n = 2 states along the He isoelectronic sequence. The strengths of various decay modes and the energy splittings of the n = 2 multiplets are investigated. At low Z the present results agree with earlier nonrelativistic studies, whereas, at high Z our results provide new information about oscillator strengths, branching ratios, and multiplet structure for the n = 2 states.

A calculation of electric and magnetic susceptibilities and shielding factors for closed-shell atomic systems based on relativistic Hartree-Fock-Slater (RHFS) electron theory is presented. Numerical results are given for the electric dipole and quadrupole, and for the magnetic dipole and octupole cases for closed-shell atoms and ions from Z-2 to Z= 92. Comparison is made with previous nonrelativistic uncoupled Hartree-Fock calculations and with experiment.