Molecular Physics seminar

Many particle coincidence experiments on molecular photoionization

by Prof. Reinhard Dörner (Johann-Wolfgang-Goethe-Universität Frankfurt)

FA32 ()


Today’s most powerful many particle imaging techniques allow to detect in coincidence the vector momenta of all electrons and ions created by fragmentation of a molecule by light. In these coincidence maps quantum correlations appear which were invisible with traditional spectroscopic techniques and allow to investigate rare species like the Helium Dimer. We will discuss two examples: For innershell ionization of N2 we find a surprising solution for the 30 year old puzzle of core hole localization. We show that and how localization arises from quantum entanglement of the photo and Auger electron. Depending on photon energy and direction of the photoelectron the Auger angular distribution shows broken or restored symmetry which directly reflects the character of the innershell hole (1). Second we will discuss how a single photon can simultaneously ionize both atoms of the Helium dimer, the most extreme quantum system among all molecules. We will show how energy can be efficiently transferred between distant sites of the Dimer (2,3). (1) Schöffler et al. Science 320, 920 (2008) (2) Havermeier et al Phys. Rev. Lett. 104, 153401 (2010) (3) Havermeier et al Phys. Rev. Lett. 104, 133401 (2010)