Attosecond time resolved ionisation spectroscopy Sampling of inner-shell processes in rare gases

Complete test of publication follows Relaxation dynamics of core-excited ions was traced by ion-population transfer in the case of XUV excited xenon Here we demonstrate, that a laser based sampling system, consisting of a few-cycle femtosecond laser pulse and a synchronised sub-femtosecond soft X-ray pulse allows us to sample these dynamics with attosecond resolution We demonstrate the tracing of inner atomic rearrangement of xenon excited by a 250 as XUV pulse carried at ℎωXUV ∼ 93,5 eV with a bandwidth FWHM (full-width at intensity half-maximum (FWHM): τL ∼ 5 fs, carrier wavelength: λL ∼ 750 nm, 3 kHz repetition rate) of ∼9 eV well above the xenon 4d → 6p resonance The ionised atoms are probed by a ℎωL ∼ 1,6 eV laser pulse and detected by an reflectron type time-of-flight ion spectrometer For weak laser pulses we trace the inner-shell processes by probing the shift in the binding energy of the outer electrons excited by the XUV In the case of xenon a ℎωXUV ∼ 93,5 eV photon produces a 4d-1 hole, which will decay through different Auger channels and create higher ionic charges Due to Auger-induced shake-up processes or direct excitation the delay dependent ionisation of the excited electron with the IR laser pulse reveals dynamics in the population of the different ionic states, which are related to the decay times of the single and double Auger channels