Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Extended Analysis of the Spectrum of Singly Ionized Chromium (Cr II)



Craig J. Sansonetti, Gillian Nave


We have made new observations of the spectrum of singly-ionized chromium (Cr II) in the region 2850 Angstrom to 37900 Angstrom with the National Institute of Standards and Technology 2 m Fourier transform spectrometer. These data extend our previously reported observations in the near ultra-violet region. We present a comprehensive list of more than 5300 Cr II lines classified as transitions among 456 even and 457 odd levels, 179 of which are newly located in this work. Using highly excited levels of the 3d4(5D)5g, 3d4(5D)6g, and 3d4(5D)6h configurations, we derive an improved ionization energy of 132971.02(12) cm -1 (16.486305+/-0.000015eV).
Astrophysical Journal Supplement Series


atomic spectra, chromium, energy levels, Fourier transform spectroscopy, infrared, ionization energy, wavelengths


Sansonetti, C. and Nave, G. (2014), Extended Analysis of the Spectrum of Singly Ionized Chromium (Cr II), Astrophysical Journal Supplement Series, [online], (Accessed June 24, 2024)


If you have any questions about this publication or are having problems accessing it, please contact

Created July 23, 2014, Updated July 7, 2023