Molecular Physics seminar

Delay in Photoemission

by Alexander Späh (Molecular Physics Division)

FB55 ()


They are tiny, only point-shaped and incredibly fast – electrons. They absorb and emit light, carry electric current and bind atoms together to form molecules. Many fundamental electronic processes, e.g. photoionization, electron tunneling, coherent XUV emission and charge transport, rely on the atomic scale motion of electrons, which elapses on an attosecond time scale (1as=10-18s). Consequently, generating access to time-resolved intra-atomic electron dynamics requires controllable chronometry signals of comparable duration, lasting only billionths of a billionth of a second, i.e. attoseconds. Using the method of attosecond streaking spectroscopy, enables time-resolved investigation of photoelectron emission and reveals relative temporal delays between electrons that originate from different electronic states. However, despite various theoretical studies which aim to explain the measured relative delay, its origin is still unclear. Not least because of unknown absolute emission times, none of the theoretical approaches could be favored to date. For this purpose, a new gas-phase attosecond streaking experiment is running up, which will quantify absolute photoelectron emission times for the first time.