NIST Atomic Ionization Energies Output

Example of how to reference these results:
Kramida, A., Ralchenko, Yu., Reader, J., and NIST ASD Team (2024). NIST Atomic Spectra Database (ver. 5.12), [Online]. Available: https://physics.nist.gov/asd [2026, November 3]. National Institute of Standards and Technology, Gaithersburg, MD. DOI: https://doi.org/10.18434/T4W30F

BibTex Citation (new window)

Ionization Energy (eV)
6.56149
12.79977
24.756839
73.4894
[91.95]
[110.68]
[137.99]
[158.08]
180.03
[225.18]
[249.798]
687.36
[757.7]
[833.2]
[926.5]
[1 008.6]
[1 093.5]
[1 213.1]
(1 287.957)
(5 674.9036)
(6 033.75643)
6.828120
13.5755
27.49171
43.26717
99.299
[119.533]
[140.68]
[170.5]
[192.1]
215.92
[265.07]
[291.500]
787.67
[864.0]
[944.5]
[1 042.5]
[1 130.2]
[1 220.3]
[1 346.3]
(1 425.257)
(6 249.0226)
(6 625.81023)
6.746187
14.634
29.3111
46.709
65.28165
128.125
[150.72]
[173.55]
[206.0]
[230.5]
[254.8]
[308.5]
[336.274]
896.0
[977.2]
[1 062.9]
[1 165.2]
[1 258.9]
[1 354.2]
[1 486.7]
(1 569.656)
(6 851.3112)
(7 246.12624)
6.76651
16.486305
30.959
[49.16]
[69.46]
90.6349
[160.29]
[184.76]
[209.5]
[244.5]
[270.8]
[296.7]
[354.7]
[384.163]
[1 011.6]
[1 097.2]
[1 188.0]
[1 294.8]
[1 394.5]
[1 495.1]
[1 634.1]
(1 721.183)
(7 481.8624)
(7 894.80289)
7.4340380
15.63999
33.668
[51.21]
[72.41]
95.604
119.203
[195.5]
[221.89]
[248.6]
[286.1]
[314.4]
[343.6]
[402.95]
[435.172]
[1 133.7]
[1 224.1]
[1 320.3]
[1 430.9]
[1 537.2]
[1 643.2]
[1 788.7]
(1 879.873)
(8 140.7864)
(8 571.95438)
7.9024681
16.19921
30.651
54.91
[75.00]
98.985
124.9671
151.060
[233.6]
[262.10]
[290.9]
[330.8]
[361.0]
[392.2]
456.2
[489.312]
[1 262.7]
[1 357.8]
[1 460]
1 575.6
[1 687.0]
[1 798.4]
[1 950.4]
(2 045.759)
(8 828.1864)
(9 277.6886)
7.88101
17.0844
[33.50]
[51.27]
[79.50]
[102.00]
[128.9]
[157.8]
186.14
[275.4]
[305.32]
[336.1]
[378.5]
[410.0]
[441.1]
[511.96]
[546.588]
1 397.2
1 504.5
[1 606]
[1 724]
[1 844.0]
[1 960.8]
[2 119.4]
(2 218.876)
(9 544.1817)
(10 012.1297)
7.639878
18.168838
35.187
[54.92]
[76.06]
[108.0]
(132.0)
(162.0)
[193.2]
[224.7]
[319.5]
[351.6]
[384.5]
[429.3]
[462.8]
[495.4]
[571.07]
[607.020]
1 540.1
[1 646]
[1 758]
[1 880]
[2 008.1]
[2 130.5]
[2 295.6]
(2 399.259)
(10 288.8848)
(10 775.3948)
7.726380
20.29239
36.841
[57.38]
[79.8]
[103.0]
[139.0]
(166.0)
(198.0)
[232.2]
265.33
[367.0]
[401.0]
[436.0]
[483.1]
[518.7]
[552.8]
[632.5]
[670.608]
[1 690.5]
[1 800]
[1 918]
[2 044]
[2 179.4]
[2 307.3]
[2 479.1]
(2 586.954)
(11 062.4309)
(11 567.6237)
9.394197
17.96439
39.72330
59.573
[82.6]
[108.0]
[133.9]
[173.9]
[203.0]
(238.0)
[274.4]
[310.8]
[417.6]
[453.4]
[490.6]
[540.0]
[577.8]
[613.3]
[697.5]
[737.366]
[1 846.8]
[1 961]
[2 085]
[2 214]
[2 358.0]
[2 491.5]
[2 669.9]
(2 781.996)
(11 864.9401)
(12 388.9427)

Ionization Energy
(eV)

6.56149

12.79977

24.756839

73.4894

[91.95]

[110.68]

[137.99]

[158.08]

180.03

[225.18]

[249.798]

687.36

[757.7]

[833.2]

[926.5]

[1 008.6]

[1 093.5]

[1 213.1]

(1 287.957)

(5 674.9036)

(6 033.75643)

6.828120

13.5755

27.49171

43.26717

99.299

[119.533]

[140.68]

[170.5]

[192.1]

215.92

[265.07]

[291.500]

787.67

[864.0]

[944.5]

[1 042.5]

[1 130.2]

[1 220.3]

[1 346.3]

(1 425.257)

(6 249.0226)

(6 625.81023)

6.746187

14.634

29.3111

46.709

65.28165

128.125

[150.72]

[173.55]

[206.0]

[230.5]

[254.8]

[308.5]

[336.274]

896.0

[977.2]

[1 062.9]

[1 165.2]

[1 258.9]

[1 354.2]

[1 486.7]

(1 569.656)

(6 851.3112)

(7 246.12624)

6.76651

16.486305

30.959

[49.16]

[69.46]

90.6349

[160.29]

[184.76]

[209.5]

[244.5]

[270.8]

[296.7]

[354.7]

[384.163]

[1 011.6]

[1 097.2]

[1 188.0]

[1 294.8]

[1 394.5]

[1 495.1]

[1 634.1]

(1 721.183)

(7 481.8624)

(7 894.80289)

7.4340380

15.63999

33.668

[51.21]

[72.41]

95.604

119.203

[195.5]

[221.89]

[248.6]

[286.1]

[314.4]

[343.6]

[402.95]

[435.172]

[1 133.7]

[1 224.1]

[1 320.3]

[1 430.9]

[1 537.2]

[1 643.2]

[1 788.7]

(1 879.873)

(8 140.7864)

(8 571.95438)

7.9024681

16.19921

30.651

54.91

[75.00]

98.985

124.9671

151.060

[233.6]

[262.10]

[290.9]

[330.8]

[361.0]

[392.2]

456.2

[489.312]

[1 262.7]

[1 357.8]

[1 460]

1 575.6

[1 687.0]

[1 798.4]

[1 950.4]

(2 045.759)

(8 828.1864)

(9 277.6886)

7.88101

17.0844

[33.50]

[51.27]

[79.50]

[102.00]

[128.9]

[157.8]

186.14

[275.4]

[305.32]

[336.1]

[378.5]

[410.0]

[441.1]

[511.96]

[546.588]

1 397.2

1 504.5

[1 606]

[1 724]

[1 844.0]

[1 960.8]

[2 119.4]

(2 218.876)

(9 544.1817)

(10 012.1297)

7.639878

18.168838

35.187

[54.92]

[76.06]

[108.0]

(132.0)

(162.0)

[193.2]

[224.7]

[319.5]

[351.6]

[384.5]

[429.3]

[462.8]

[495.4]

[571.07]

[607.020]

1 540.1

[1 646]

[1 758]

[1 880]

[2 008.1]

[2 130.5]

[2 295.6]

(2 399.259)

(10 288.8848)

(10 775.3948)

7.726380

20.29239

36.841

[57.38]

[79.8]

[103.0]

[139.0]

(166.0)

(198.0)

[232.2]

265.33

[367.0]

[401.0]

[436.0]

[483.1]

[518.7]

[552.8]

[632.5]

[670.608]

[1 690.5]

[1 800]

[1 918]

[2 044]

[2 179.4]

[2 307.3]

[2 479.1]

(2 586.954)

(11 062.4309)

(11 567.6237)

9.394197

17.96439

39.72330

59.573

[82.6]

[108.0]

[133.9]

[173.9]

[203.0]

(238.0)

[274.4]

[310.8]

[417.6]

[453.4]

[490.6]

[540.0]

[577.8]

[613.3]

[697.5]

[737.366]

[1 846.8]

[1 961]

[2 085]

[2 214]

[2 358.0]

[2 491.5]

[2 669.9]

(2 781.996)

(11 864.9401)

(12 388.9427)

NIST Atomic Spectra Database Ionization Energies Data Multiple spectra 255 Data Rows Found	Example of how to reference these results: Kramida, A., Ralchenko, Yu., Reader, J., and NIST ASD Team (2024). NIST Atomic Spectra Database (ver. 5.12), [Online]. Available: https://physics.nist.gov/asd [2026, November 3]. National Institute of Standards and Technology, Gaithersburg, MD. DOI: https://doi.org/10.18434/T4W30F BibTex Citation (new window)