We apply time-dependent R-matrix theory to study inner-shell ionization of C atoms in ultra-short high-frequency light fields with a photon energy between 170 and 245 eV. At an intensity of 1017 W/cm2, ionization is dominated by single-photon emission of a 2l electron, with two-photon emission of a 1s electron accounting for about 2-3% of all emission processes, and two-photon emission of 2l contributing about 0.5-1%. Three-photon emission of a 1s electron is estimated to contribute about 0.01-0.03%. Around a photon energy of 225 eV, two-photon emission of a 1s electron, leaving C+ in either 1s2s2p3 or 1s2p4 is resonantly enhanced by intermediate 1s2s22p3 states. The results demonstrate the capability of time-dependent R-matrix theory to describe inner-shell ionization processes including rearrangement of the outer electrons.
|Number of pages||7|
|Journal||Physical Review A (Atomic, Molecular, and Optical Physics)|
|Publication status||Published - 21 Jul 2015|