Thursday, 13 February 2025 11:00am – 12:00pm

This seminar will be delivered in Chemistry Lecture Theatre 4

Speaker: Professor Thomas Jagau

Host: Prof. Peter Gill

Title: Non-Hermitian quantum chemistry for nonradiative decay processes

Abstract: The interaction of matter with radiation can lead to metastable electronic states that decay non-radiatively by emission of electrons. This includes high-energy processes such as Auger decay of core-ionized states, where electrons with energies of hundreds or even thousands of electron volts are emitted, as well as low-energy processes such as Coster-Kronig decay, interatomic/intermolecular Coulombic decay, and decay of Rydberg states, where the emitted electrons have energies of a few or even less than one electron volt.

The theoretical modeling of nonradiative decay is difficult because the initial states are embedded in the ionization continuum and not L2-integrable. An elegant approach to decaying states is afforded by complex scaling and the method of complex basis functions. They produce Hamiltonians with complex eigenvalues from which total and partial decay widths can be extracted. I will review the theory of these non-Hermitian techniques and show how they can be integrated into molecular electronic-structure theory. Our numerical results indicate that complex-scaled coupled-cluster methods are well suited for a broad range of autoionization phenomena.

Bio:

• 04/2020 Associate Professor, Department of Chemistry, KU Leuven, Belgium.
• 10/2015-03/2020 Leader of an independent research group, Department of Chemistry, University of Munich, Germany.
• 07/2013-09/2015 Postdoc, University of Southern California, Los Angeles, USA, advisor: Anna Krylov.
• 12/2009-04/2013 PhD in Theoretical Chemistry, University of Mainz, Germany, advisor: Jürgen Gauss.
• 10/2004-10/2009 Study of Chemistry, University of Mainz, Germany.

Recognitions:

• 2023 Dirac Medal, World Association of Theoretical and Computational Chemists
• 2019 ERC Starting Grant, TCUBE (Theoretical Chemistry of Unbound Electrons), European Research Council
• 2019 Hans G.A. Hellmann Award, Association of German Theoretical Chemists
• 2019 Ernst Haage Award, Max Planck Institutes of Chemical Energy Conversion and of Coal Research
• 2017 Emmy Noether Grant, German Research Foundation