K-shell photoabsorption edge of a dense aluminum plasma

A theoretical model for the calculation of the K-shell photoabsorption edge in a dense plasma is described. In the model, degeneracy and continuum lowering contributions due to free electrons and neighboring ions were treated as perturbations on the continuum and the bound state. These contributions were evaluated using first-principles solid-state methods. The model was used to interpret recently observed shifts in the K-shell photoabsorption-edge energy in shock-compressed aluminum. The validity of the model was further examined through comparisons with two average-atom, self-consistent-field calculations and an augmented-plane-wave calculation.