McElroy, Robert D .; Clark, David D .; Gill, R . L .; Piotrowski, A . Direct measurement of natural line widths in delayed-neutron energy spectra.
2.
Where \ Gamma is the natural line width of the excited state, \ mu is the electric dipole coupling, \ omega _ o is the frequency of the transition, and \ delta is the defining or difference between the laser frequency and the transition frequency.