Branching fractions were measured for electric-dipole transitions from the 5 p upper levels to
the 5 s levels in neutral krypton atoms. The measurements were made with a wall-stabilized
electric arc and a 2-m monochromator for the spectral lines in the visible, and with a hollow
cathode lamp and the NIST 2-m Fourier-transform spectrometer for the lines in the near
infrared. A semiempirical calculation, based on accurately known lifetimes for six upper
levels, was used to calculate lifetimes for which accurate measurements do not exist. This …

The transitions from the 5p levels to 5s levels in neutral Kr give rise to the most prominent
lines in the Kr I emission spectrum (see Fig. 1 for a simplified energy level diagram).
Lifetimes with sub-percent uncertainties for six of the ten 5p levels have recently been
measured with beam-gas laser spectroscopy (BGLS) by Schmoranzer and Volz [1] and
Schmitt et al.[2]. We will show below how the six lifetimes from BGLS can be used in an
intermediate coupling calculation to predict accurately the lifetimes of those four levels that …