Photoionization of helium by attosecond pulses: Extraction of spectra from correlated wave functions
2013 (English)In: Physical Review A. Atomic, Molecular, and Optical Physics, ISSN 1050-2947, E-ISSN 1094-1622, Vol. 87, no 5, 053405- p.Article in journal (Refereed) Published
We investigate the photoionization spectrum of helium by attosecond XUV pulses both in the spectral region of doubly excited resonances as well as above the double ionization threshold. In order to probe for convergence, we compare three techniques to extract photoelectron spectra from the wave packet resulting from the integration of the time-dependent Schrodinger equation in a finite-element discrete variable representation basis. These techniques are projection on products of hydrogenic bound and continuum states, projection onto multichannel scattering states computed in a B-spline close-coupling basis, and a technique based on exterior complex scaling implemented in the same basis used for the time propagation. These methods allow one to monitor the population of continuum states in wave packets created with ultrashort pulses in different regimes. Applications include photo cross sections and anisotropy parameters in the spectral region of doubly excited resonances, time-resolved photoexcitation of autoionizing resonances in an attosecond pump-probe setting, and the energy and angular distribution of correlated wave packets for two-photon double ionization.
Place, publisher, year, edition, pages
2013. Vol. 87, no 5, 053405- p.
Atom and Molecular Physics and Optics
IdentifiersURN: urn:nbn:se:su:diva-91527DOI: 10.1103/PhysRevA.87.053405ISI: 000319054000011OAI: oai:DiVA.org:su-91527DiVA: diva2:634690
FunderSwedish Research CouncilEU, European Research Council, 290853, 290981 (PLASMONANOQUANTA