Analysis of the resonant Auger decay during ultrafast fragmentation of CH3F

After inner shell excitation the ultrafast fragmentation of small molecules can proceed on a time scale similar to that of the Auger decay. In this case the nuclear motion affects the observed electron spectrum in various ways. The best known example is the Doppler splitting of atomiclike Auger lines, but non-parallel potential surfaces are equally important. Using an electron energy - ion momentum coincidence experiment and an ab initio calculation of potential curves, we discuss the main features seen in the non-coincident and coincident resonant Auger spectrum by decay of the F(1s)->6a1* core excited state of CH3F.