Speaker
Description
Photoemission orbital tomography (POT) is a combined experimental and theoretical technique that provides an intuitive understanding of angle-resolved photoemission spectroscopy (ARPES) in terms of electronic orbitals. The theoretical framework was recently extended to describe photoemission from excited states of gas-phase molecular systems [1], enabling theoretical insights into pump-probe ARPES experiments.
In this contribution, we present a further development toward photoemission from optically excited states in periodic systems. We derive a formula that allows for the computation of photoemission angular distributions based on GW/BSE results, discuss the approximations involved, and provide technical details of our implementation [2]. Finally, we demonstrate the capabilities of our approach on the example of an organic molecular layer (sexithiophene, [3]) and compare our predictions to corresponding time-resolved ARPES experiments. In particular, we show how the observed photoemission momentum pattern is related to the composition (BSE eigenvector) of the optically excited state and how information about the excited state’s wavefunction may therefore be extracted from experimentally obtained momentum distributions.
References:
[1] Kern et al., Phys. Rev. B 108, 085132 (2023)
[2] Kaidisch et al., arXiv: 2511.14956 (2025)
[3] Theilen et al., arXiv:2511.23001 (2025)