Accurate nonrelativistic energies for the lowest 4S states of Li

Lifetimes for the 1s2sns4S states of lithium

“…For example, for the 1s2s2p 4 P state, the energy of Barrois et al [14] (for the case of infinite nuclear mass) is −5.368 0101 au, whereas ours is −5.368 010 1539(2) au. For the 1s2s6s 4 S state, the results of Lüchow et al [12] and Qu et al [15] are −5.128 880 and −5.128 9012 au respectively. Compared to our value of −5.128 881 179(1) au, which is in good accord with the value of Lüchow et al, the calculation of Qu et al is obviously in error in the last four digits, because a variational calculation should result in an upper bound of the true energy eigenvalue.…”

“…For the sake of completeness, we included the first three energies of S symmetry which were published previously [8]. Although some of those states were calculated by Kleindienst and collaborators [12][13][14] and by Qu et al [15] using Hylleraas coordinates and the full core plus correlation (FCPC) method respectively, our results are more accurate than theirs. For example, for the 1s2s2p 4 P state, the energy of Barrois et al [14] (for the case of infinite nuclear mass) is −5.368 0101 au, whereas ours is −5.368 010 1539(2) au.…”

Non-relativistic energies for the low-lying quartet S states of lithium

“…The quartet states were also studied by Bunge and co-workers [7,8] and by Hsu et al [9] using the configuration-interaction (CI) method. More accurate non-relativistic energies for some quartet states of lithium and lithium-like ions were obtained recently by Lüchow et al [10] and Barrois et al [11] using Hylleraas coordinates. The non-relativistic energies of a number of quartet states were also calculated variationally in Hylleraas coordinates and estimated semiempirically by King [12].…”

“…1 can also be solved from equation (14) variationally using similar basis sets in Hylleraas coordinates. Table 3 contains the values of 0 , 1 and 2 for the first three quartet S states, together with a comparison with Barrois et al [11] and Lüchow et al [10], for the coefficient 1 calculations. It can be seen that the results of Barrois et al and Lüchow et al for 1 appear not to have converged to all the digits displayed.…”

High-precision calculations of the hyperfine constants and some selected transition energies for the low-lying 4 S levels of the lithium atom

“…The excited quartet levels of the lithium atom have attracted considerable experimental and theoretical attention, though these levels have been studied significantly less extensively than both the ground state and some of the low‐lying excited levels of various symmetries for this atomic system …”