NIST Atomic Ionization Energies Output

NIST Physical Measurement Laboratory

NIST Atomic Spectra Database Ionization Energies Data Db (all spectra) 94 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, October 26]. National Institute of Standards and Technology, Gaithersburg, MD. DOI: https://doi.org/10.18434/T4W30F BibTex Citation (new window)

Ionization Energy ^a (cm^-1)
(55 000)
(113 000)
(186 000)
(266 000)
(347 000)
(694 000)
(798 000)
(1 016 000)
(1 170 000)
(1 387 000)
(1 581 000)
(1 782 000)
(2 049 000)
(2 210 000)
(2 476 000)

(6 759 000)
(7 033 000)
(7 324 000)
(7 646 000)
(7 945 000)
(8 243 000)
(8 783 000)
(9 082 000)
(9 421 000)
(9 735 000)






















(32 061 000)
(32 722 000)
(33 432 000)
(34 174 000)
(34 892 000)
(35 577 000)
(37 255 000)
(37 981 000)
(38 763 000)
(39 497 000)
(42 465 000)
(43 159 000)
(43 925 000)
(44 635 000)
(50 635 000)
(51 490 000)
(53 668 000)
(54 515 000)
(84 051 000)
(85 608 000)
(87 253 000)
(89 011 000)
(90 681 000)
(92 294 000)
(97 077 000)
(98 795 000)
(100 690 000)
(102 432 000)
(107 312 000)
(108 804 000)
(110 433 000)
(111 950 000)
(130 371 000)
(132 291 000)
(136 098 000)
(137 872 000)
(272 438 000)
(276 438 000)
(280 907 000)
(284 972 000)
(353 061 000)
(359 102 000)
(366 369 000)

(1 439 737 000)
(1 463 450 000)

Notes:
^aIf the listed ionization energy is blank, it is unknown. Only the ground state is known.
^bUncertainty of the listed value is unknown.

If you did not find the data you need, please inform the ASD Team.

NIST Physical Measurement Laboratory