We present a precise measurement of the photoexcited F $K\alpha$ satellite intensity’s evolution for NaF from $[1s2p]$ double excitation threshold to saturation. A direct comparison between the observed evolution and the x-ray absorption spectrum was successfully made, and the contribution of multielectron transitions to the absorption spectrum was clearly resolved for the first time. A resonancelike feature observed in the near-threshold evolution is attributed to the $[1s2p]3p^2$ resonant double excitation as confirmed by calculations.

• Received 18 February 2002

DOI:https://doi.org/10.1103/PhysRevLett.90.173002