Variational upper bounds for low-lying states of lithium

We present improved calculations of variational energy eigenvalues for the 1s{sup 2}2s {sup 2}S, 1s{sup 2}3s {sup 2}S, and 1s{sup 2}2p {sup 2}P states of lithium using basis sets with up to 30 224 terms in Hylleraas coordinates. The nonrelativistic energies for infinite nuclear mass are -7.478 060 323 910 143 7(45) a.u. for 1s{sup 2}2s {sup 2}S, -7.354 098 421 444 316 4(32) a.u. for 1s{sup 2}3s {sup 2}S, and -7.410 156 532 651 6(5) a.u. for 1s{sup 2}2p {sup 2}P, which represent the most accurate variational upper bounds to date. An important advantage of the basis sets with multiple distance scales is their exceptional numerical stability.