NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
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.
Eric Norrgard, Daniel Barker, Stephen Eckel, Sergey Porsev, Charles Cheung, Mikhail Kozlov, Ilya Tupitsyn, Marianna Safronova
Abstract
Here we report measured and calculated values of decay rates of the 3d$^4$($^5$D)4s4p($^3$P$^\rmo}}$)\ y$^7$P$^\rmo}}_2,3,4}$ states of Cr I. The decay rates are measured using time-correlated single photon counting with roughly 1\,\% total uncertainty. In addition, the isotope shifts for these transitions are measured by laser induced fluorescence to roughly 0.5\,\% uncertainty. The decay rate calculations are carried out by a hybrid approach that combines configuration interaction and the linearized coupled cluster method (CI+all-order method). The measurements provide a much needed precision benchmark for testing the accuracy of the CI+all-order approach for such complicated systems with six valence electrons, allowing to significantly expand its applicability. These measurements also demonstrate operation of a cryogenic buffer gas beam source for future experiments with MgF molecules toward quantum blackbody thermometry.
Norrgard, E.
, Barker, D.
, Eckel, S.
, Porsev, S.
, Cheung, C.
, Kozlov, M.
, Tupitsyn, I.
and Safronova, M.
(2022),
Laser Spectroscopy of the y7PJo states of Cr I, Physical Review A, [online], https://doi.org/10.1103/PhysRevA.105.032812, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=933666
(Accessed October 8, 2025)