Values for first and second spectra are from NIST (II's courtesy of Jean
Sansonetti), except for At I, from HCP.
Most other entries are from Handbook of Chemistry and Physics, 3rd electronic
edition. Additional entries are from Dappen (AQ IV, 2000) or Cowan (1987).
Most of the Dappen values are given to the nearest electron volt, though
In IV, Tl IV, and At I are given to the tenth of an eV. Some entries
for the REE third and fourth spectra were given by Cowan to the hundredth
of an eV, and those values are reproduced here, though they are surely
uncertain.
It is amazing that we know the second ionization energies of several 5d
elements only to the nearest eV. Y II is from Phys. Scr. 44, 226
(1991).
Hydrogen H 1 13.5984
Helium He 2 24.5874 54.417760
Lithium Li 3 5.3917 75.6400 122.45429
Beryllium Be 4 9.3227 18.21114 153.89661 217.71865
Boron B 5 8.2980 25.1548 37.93064 259.37521 340.22580
Carbon C 6 11.2603 24.3833 47.8878 64.4939 392.087
Nitrogen N 7 14.5341 29.6013 47.44924 77.4735 97.8902
Oxygen O 8 13.6181 35.1211 54.9355 77.41353 113.8990
Fluorine F 9 17.4228 34.9708 62.7084 87.1398 114.2428
Neon Ne 10 21.5646 40.96296 63.45 97.12 126.21
Sodium Na 11 5.1391 47.2864 71.6200 98.91 138.40
Magnesium Mg 12 7.6462 15.03527 80.1437 109.2655 141.27
Aluminum Al 13 5.9858 18.82855 28.44765 119.992 153.825
Silicon Si 14 8.1517 16.34584 33.49302 45.14181 166.767
Phosphorus P 15 10.4867 19.7695 30.2027 51.4439 65.0251
Sulfur S 16 10.3600 23.33788 34.79 47.222 72.5945
Chlorine Cl 17 12.9676 23.8136 39.61 53.4652 67.8
Argon Ar 18 15.7596 27.62965 40.74 59.81 75.02
Potassium K 19 4.3407 31.63 45.806 60.91 82.66
Calcium Ca 20 6.1132 11.87172 50.9131 67.27 84.50
Scandium Sc 21 6.5615 12.79977 24.75666 73.4894 91.65
Titanium Ti 22 6.8281 13.5755 27.4917 43.2672 99.30
Vanadium V 23 6.7462 14.618 29.311 46.709 65.2817
Chromium Cr 24 6.7665 16.4857 30.96 49.16 69.46
Manganese Mn 25 7.4340 15.6400 33.668 51.2 72.4
Iron Fe 26 7.9024 16.1877 30.652 54.8 75.0
Cobalt CO 27 7.8810 17.084 33.50 51.3 79.5
Nickel Ni 28 7.6398 18.16884 35.19 54.9 76.06
Copper Cu 29 7.7264 20.2924 36.841 57.38 79.8
Zinc Zn 30 9.3942 17.96439 39.723 59.4 82.6
Gallium Ga 31 5.9993 20.51514 30.71 64 87
Germanium Ge 32 7.8994 15.93461 34.2241 45.7131 93.5
Arsenic As 33 9.7886 18.5892 28.351 50.13 62.63
Selenium Se 34 9.7524 21.19 30.8204 42.9450 68.3
Bromine Br 35 11.8138 21.591 36. 47.3 59.7
Krypton Kr 36 13.9996 24.35984 36.950 52.5 64.7
Rubidium Rb 37 4.1771 27.2895 40 52.6 71.0
Strontium Sr 38 5.6949 11.0301 42.89 57 71.6
Yttrium Y 39 6.2171 12.22 20.52 60.597 77.0
Zirconium Zr 40 6.6339 13.1 22.99 34.34 80.348
Niobium Nb 41 6.7589 14.0 25.04 38.3 50.55
Molybdenum Mo 42 7.0924 16.16 27.13 46.4 54.49
Technetium Tc 43 7.28 15.26 29.54 46 55
Ruthenium Ru 44 7.3605 16.76 28.47 50 60
Rhodium Rh 45 7.4589 18.08 31.06 48 65
Palladium Pd 46 8.3369 19.43 32.93 53 62
Silver Ag 47 7.5762 21.47746 34.83 56 68
Cadmium Cd 48 8.9938 16.90831 37.48 59 72
Indium In 49 5.7864 18.8703 28.03 54.4 77
Tin Sn 50 7.3439 14.6322 30.50260 40.73502 72.28
Antimony Sb 51 8.6084 16.63 25.3 44.2 56
Tellurium Te 52 9.0096 18.6 27.96 37.41 58.75
Iodine I 53 10.4513 19.1313 33 42 66
Xenon Xe 54 12.1298 20.9750 32.1230 46 57
Cesium Cs 55 3.8939 23.15744 35 46 62
Barium Ba 56 5.2117 10.00383 35.84 49 62
Lanthanum La 57 5.5769 11.059 19.1773 49.95 61.6
Cerium Ce 58 5.5387 10.85 20.198 36.758 65.55
Praseodymium Pr 59 5.473 10.55 21.624 38.98 57.53
Neodymium Nd 60 5.5250 10.72 22.1 40.4 60.00
Promethium Pm 61 5.582 10.90 22.3 41.1 61.69
Samarium Sm 62 5.6436 11.07 23.4 41.4 62.66
Europium Eu 63 5.6704 11.25 24.92 42.7 63.23
Gadolinium Gd 64 6.1501 12.09 20.63 44.0 64.76
Terbium Tb 65 5.8638 11.52 21.91 39.79 66.46
Dysprosium Dy 66 5.9389 11.67 22.8 41.47 62.08
Holmium Ho 67 6.0215 11.80 22.84 42.5 63.93
Erbium Er 68 6.1077 11.93 22.74 42.7 65.10
Thulium Tm 69 6.1843 12.05 23.68 42.7 65.42
Ytterbium Yb 70 6.2542 12.176 25.05 43.56 65.58
Lutetium Lu 71 5.4259 13.9 20.9594 45.25 66.8
Hafnium Hf 72 6.8251 15 23.3 33.33 68.38
Tantalum Ta 73 7.5496 16 22 33 45
Tungsten W 74 7.8640 16.1 24 35 48
Rhenium Re 75 7.8335 17 26 38 51
Osmium Os 76 8.4382 17 25 40 54
Iridium Ir 77 8.9670 17 27 39 57
Platinum Pt 78 8.9587 18.563 28 41 55
Gold Au 79 9.2255 20.20 30 44 58
Mercury Hg 80 10.4375 18.7568 34.2 46 61
Thallium Tl 81 6.1082 20.4283 29.83 50.7 64
Lead Pb 82 7.4167 15.03248 31.9373 42.32 68.8
Bismuth Bi 83 7.2856 16.703 25.56 45.3 56.0
Polonium Po 84 8.417 ? 19 27 38 61
Astatine At 85 9.3 20 29 41 51
Radon Rn 86 10.7485 21 29 44 55
Francium Fr 87 4.0727 22 33 43 59
Radium Ra 88 5.2784 10.14715 34 46 58
Actinium Ac 89 5.17 11.75 20 49 62
Thorium Th 90 6.3067 11.9 20.0 28.8 65
Protactinium Pa 91 5.89
Uranium U 92 6.1941 10.6
Neptunium Np 93 6.2657
Plutonium Pu 94 6.0262 11.2
Americium Am 95 5.9738
Curium Cm 96 5.9915
Berkelium Bk 97 6.1979
Californium Cf 98 6.2817 11.8
Einsteinium Es 99 6.42 12.0
Fermium Fm 100 6.50