20,068 research outputs found
Radiation Damping in the Photoionization of Fe^{14+}
A theoretical investigation of photoabsorption and photoionization of
Fe^{14+} extending beyond an earlier frame transformation R-matrix
implementation is performed using a fully-correlated, Breit-Pauli R-matrix
formulation including both fine-structure splitting of strongly-bound
resonances and radiation damping. The radiation damping of
resonances gives rise to a resonant photoionization cross section that is
significantly lower than the total photoabsorption cross section. Furthermore,
the radiation-damped photoionization cross section is found to be in good
agreement with recent experimental results once a global shift in energy of
eV is applied. These findings have important implications.
Firstly, the presently available synchrotron experimental data are applicable
only to photoionization processes and not to photoabsorption; the latter is
required in opacity calculations. Secondly, our computed cross section, for
which the L-shell ionization threshold is aligned with the NIST value, shows a
series of Rydberg resonances that are uniformly 3-4 eV
higher in energy than the corresponding experimental profiles, indicating that
the L-shell threshold energy values currently recommended by NIST are likely in
error.Comment: 4 pages, 1 figures, and 2 table
UCL (University College London) Libraries Masterplan: Library Report to Estates Management Committee January 2008
This document is a Report from UCL Library Services to UCL on Master Planning
activities and outputs which have been undertaken to quantify use and
development of estate in UCL Library Services. Prioritised options have been
identified for the UCL Main and Science Libraries, and for a new central site
option. This work has also addressed the needs of UCL for long-term offsite
storage, which concludes that UCL needs to retain its facility at Wickford for at
least the next ten years
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