Lithium Energy Levels

The lithium atom has a closed n=1 shell with two electrons and then one electron outside. Since the outer electron looks inward at just one net positive charge, it could be expected to have energy levels close to those of hydrogen. This is true for high angular momentum states as shown, but the s and p states fall well below the corresponding hydrogen energy levels. 锂原子有n=1层的闭合壳层，其中有两个电子，然后有一个电子在外层。由于外层电子只看到一个净正电荷，因此可以预期其能级接近氢原子的能级。这在高角动量态中得到证实，但s和p态却明显低于相应的氢原子能级。

The general layout here was taken from Rohlf but some discrepancies were found in the lower levels. The levels up through the 3d plus the 4p and 4d were rescaled to fit the data in the table of neutral lithium levels from NIST. Discrepancies may remain with the other levels. The ionization potential given by NIST was 5.395 eV.

Lithium Energy Levels:Orbital Dependence

The lithium 2s level is significantly lower than the 2p because of greater penetration past the shielding of the 1s electron. Both levels penetrate enough to be significantly lower than the n=2 hydrogen energy which they would have if the shielding were perfect. 锂的2s能级显著低于2p能级，这是因为其更深入地穿透了1s电子的屏蔽作用。两个能级都足够穿透，因此它们的能级显著低于若屏蔽完全理想时的n=2氢原子能级。 The 2s electron is lowered about 1.7 eV below the n=2 hydrogenic energy level of -3.4 eV which it would have if the shielding were perfect. 2s电子的能量比完美屏蔽情况下n=2的氢原子能级-3.4 eV降低了约1.7 eV。