Two-electronSandPterm values with smoothZdependence

Perturbation and extrapolation techniques based on expansion in inverse powers of the atomic number $Z$ have recently been used to estimate term values for $S$ and $P$ states of heliumlike atoms in the intermediate range of values of $Z$. The coefficients in these expansions are determined by utilizing the accurate data currently available for values of $Z\le 10$. In order to obtain optimum results from such techniques, the data for low values of $Z$ should exhibit a smooth variation with atomic number. To meet this requirement, the paper lists smooth values for the nonrelativistic energy and the relativistic corrections for the ground state and the states $n{}_{}{}^1{}_{}{}^{}S$, $n{}_{}{}^3{}_{}{}^{}S$, $n{}_{}{}^1{}_{}{}^{}P$, and $n{}_{}{}^3{}_{}{}^{}P$, $n=2-5\mathrm{}$ for $Z=2-10\mathrm{}$. Smooth behavior with $Z$ has been ensured by quoting, for a given state, values obtained using the same type and length of expansion for the wave function. Also, the effect of rounding errors has been minimized by quoting the original values obtained in atomic units, and by listing the numbers to one or two digits more than would be justified by convergence arguments.