NIST Atomic Ionization Energies Output

NIST Physical Measurement Laboratory

NIST Atomic Spectra Database Ionization Energies Data Ds (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)
(524 000)


(911 000)
(1 032 000)
(1 742 000)
(1 863 000)
(2 145 000)
(2 323 000)
(2 597 000)
(2 839 000)
(3 065 000)
(3 404 000)
(3 565 000)
(3 896 000)

(8 767 000)
(9 074 000)
(9 396 000)
(9 745 000)
(10 078 000)
(10 405 000)
(11 042 000)
(11 389 000)
(11 751 000)
(12 098 000)






















(37 021 000)
(37 739 000)
(38 489 000)
(39 287 000)
(40 045 000)
(40 779 000)
(42 755 000)
(43 530 000)
(44 369 000)
(45 151 000)
(48 337 000)
(49 071 000)
(49 893 000)
(50 652 000)
(58 346 000)
(59 274 000)
(61 629 000)
(62 540 000)
(94 569 000)
(96 206 000)
(97 956 000)
(99 819 000)
(101 594 000)
(103 295 000)
(108 901 000)
(110 732 000)
(112 740 000)
(114 603 000)
(119 773 000)
(121 362 000)
(123 096 000)
(124 701 000)
(148 204 000)
(150 285 000)
(154 350 000)
(156 262 000)
(301 756 000)
(305 991 000)
(310 725 000)
(315 024 000)
(401 793 000)
(408 528 000)
(416 110 000)

(1 622 080 000)
(1 648 550 000)

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