Attosecond electronic dynamics of core-excited states of N_{2}O in the soft x-ray region

Abstract

We present a combined experimental and theoretical study of the transient absorption spectroscopy of N_{2}O at the N K edge (400 eV) by employing an attosecond soft x-ray pulse and an overlapping intense femtosecond infrared pulse. Our experiment demonstrates that tunnel ionization of the core-excited states of neutral N_{2}O causes prominent half-cycle oscillations in the absorption signal. In addition, we observe the appearance of the N_{2}O^{+} signal with increasing delay as a result of the tunneling ionization of N_{2}O, thereby allowing us to follow the tunneling process in real time. We have developed theoretical models that allow us to interpret and reproduce the main trends of the experimental data.