NIST Atomic Ionization Energies Output

NIST Physical Measurement Laboratory

NIST Atomic Spectra Database Ionization Energies Data Rf (all spectra) 93 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)
(48 580)
(115 740)
(192 300)
(257 070)
(516 000)
(621 000)
(823 000)
(960 000)
(1 178 000)
(1 363 000)
(1 557 000)
(1 815 000)
(1 968 000)
(2 218 000)

(6 380 000)
(6 654 000)
(6 936 000)
(7 251 000)
(7 549 000)
(7 840 000)
(8 356 000)
(8 654 000)
(8 985 000)
(9 283 000)






















(31 109 000)
(31 762 000)
(32 464 000)
(33 198 000)
(33 899 000)
(34 577 000)
(36 206 000)
(36 916 000)
(37 690 000)
(38 416 000)
(41 336 000)
(42 021 000)
(42 780 000)
(43 481 000)
(49 192 000)
(50 031 000)
(52 176 000)
(52 999 000)
(82 027 000)
(83 559 000)
(85 180 000)
(86 930 000)
(88 576 000)
(90 165 000)
(94 802 000)
(96 504 000)
(98 367 000)
(100 093 000)
(104 900 000)
(106 376 000)
(107 998 000)
(109 490 000)
(127 040 000)
(128 928 000)
(132 678 000)
(134 420 000)
(266 768 000)
(270 728 000)
(275 140 000)
(279 157 000)
(344 028 000)
(349 940 000)
(357 126 000)

(1 405 546 000)
(1 428 750 000)

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