The dispersion coefficients C 6 , C 8 , and C 10 for the interactions between H, He, and Li are calculated using variational wave functions in Hylleraas basis sets with multiple exponential scale factors. With these highly correlated wave functions, significant improvements are made upon previous calculations and our results provide definitive values for these coefficients.

No abstract

No abstract

The dynamic dipole polarizabilities for the Li atom and the Be + ion in the 2 2 S and 2 2 P states are calculated using the variational method with a Hylleraas basis. The present polarizabilities represent the definitive values in the non-relativistic limit. Corrections due to relativistic effects are also estimated. Analytic representations of the polarizabilities for frequency ranges encompassing the n = 3 excitations are presented. The recommended polarizabilities for 7 Li and 9 Be + were 164.11 ± 0.03 a 3 0 and 24.489 ± 0.004 a 3 0 .

Calculational results are presented for the fine-structure splitting of the 2 3 P state of helium and helium-like ions with the nuclear charge Z up to 10. Theoretical predictions are in agreement with the latest experimental results for the helium fine-structure intervals as well as with the most of the experimental data available for light helium-like ions. Comparing the theoretical value of the 2 3 P0 − 2 3 P1 interval in helium with the experimental result [T. Zelevinsky et al. Phys. Rev. Lett. 95, 203001 (2005)], we determine the value of the fine-structure constant α with an accuracy of 31 parts per billion.

The long-range interactions of two atoms, of an atom and a dielectric wall, of an atom and a perfectly conducting wall, and of an atom between two perfectly conducting walls are calculated, including the effects of retardation, for Li using dynamic polarizabilities determined from highly correlated, variationally determined wave functions.

No abstract

Fully correlated calculations of the Zeeman gJ-factors for lithium-like ions in the 2 2S and 3 2S states are presented, including relativistic and radiative corrections of orders α2, α2m/M, and α3. The isotope shifts in gJ are determined accurately.