Computational investigation of static multipole polarizabilities and sum rules for ground-state hydrogenlike ions

Abstract

High-precision multipole polarizabilities, α l for l≤4 of the 1s ground state of the hydrogen isoelectronic series, are obtained from the Dirac equation using the B-spline method with Notre Dame boundary conditions. Compact analytic expressions for the polarizabilities as a function of Z with a relative accuracy of 10 -6 up to Z=100 are determined by fitting to the calculated polarizabilities. The oscillator strengths satisfy the sum rules - ifgi(l)=0 for all multipoles from l=1 to l=4. The dispersion coefficients for the long-range H-H and H-He + interactions are given. © 2012 American Physical Society.