Laser-enabled auger decay: Probing electronic correlation in the inner-valence-ionized states |
|
| Vitali Averbukh | |
| Imperial College London | |
| One of the new physical effects of Auger type discovered recently is laser-enabled Auger decay (LEAD) of vacancies that are not energetic enough to undergo normal Auger transition [1]. Here we investigate how can one use the LEAD in the single-photon (rather than in the multi-photon [1]) regime to investigate electronic correlation in the inner-valence-ionized states. We first consider 2s-ionised Ne as an example. This state is not Auger-active, since its energy is below the double ionization energy of Ne. Nevertheless, it is possible to induce a two-electron transition of Auger type, if we add a laser field to the system. Indeed, the 2p-2s recombination energy ?Ω combined with the VUV laser photon energy ?ω become sufficient to expel another one of the 2p electrons of Ne+. A closer look at the mechanism of the single-photon LEAD process reveals that it is possible only because the initial 2s-1 one-hole state has an admixture of the more complicated configurations with two holes and an electron excited to a high-energy orbital. Thus, the cross-section of the single-photon LEAD process is a direct measure of this configuration mixing. We use the first-principles ADC(2)x scheme and Stieltjes imaging technique [2] to evaluate single-photon LEAD cross-sections in ns-ionised Ne and Ar. We further discuss the single-photon laser-enabled Auger transitions in molecules, especially for those ionised molecular states for which the configuration mixing becomes overwhelming (so-called destruction of the molecular orbital picture [3]). [1] P. Ranitovic, X. M. Tong, C. W. Hogle, X. Zhou, Y. Liu, N. Toshima, M. M. Murnane & H. C. Kapteyn, Phys. Rev. Lett. 106, 053002 (2011). |