2018/12/31 by Adi Pick, Petra Ruth Kaprálová-Žďánská, Nimrod Moiseyev
Physics and Astronomy · #Advanced Chemical Physics Studies #Asymmetry #Autoionization #Fano plane #Ionization #Laser-Matter Interactions and Applications #Metastability #Photoionization #Quantum chaos and dynamical systems #Quantum defect #Spectral line #Spectral line shape #physics.atom-ph #physics.optics
paper · pdf · doi:10.1063/1.5098063
10 pages, 3 figures. arXiv admin note: text overlap with arXiv:1809.02868
arxiv created 2019/05/02 · openalex publication_date 2019/05/28 · arxiv updated 2019/06/26 · openalex created_date 2019/06/27 · openalex updated_date 2026/08/05
We present an ab initio approach for computing the photoionization spectrum near autoionization resonances in multi-electron systems. While traditional (Hermitian) theories typically require computing the continuum states, which are difficult to obtain with high accuracy, our non-Hermitian approach requires only discrete bound and metastable states, which can be accurately computed with available quantum chemistry tools. We derive a simple formula for the absorption line shape near Fano resonances, which relates the asymmetry of the spectral peaks to the phase of the complex transition dipole moment. Additionally, we present a formula for the ionization spectrum of laser-driven targets and relate the "Autler-Townes" splitting of spectral lines to the existence of exceptional points in the Hamiltonian. We apply our formulas to compute the autoionization spectrum of helium, but our theory is also applicable for nontrivial multi-electron atoms and molecules.